139-500: (Redirected from N02 ) N2 or N-2 may refer to: Dinitrogen (N₂) Arts and media [ edit ] A model number of the Yamaha AvantGrand piano "N2", a 2011 song by Japanese indie rock band Asian Kung-Fu Generation, on the album Landmark Network 2 (now RTÉ Two ), an Irish television station, which used the branding "N2" between 1997-2004 NicoNico ,
278-514: A dinitrogen complex to be discovered was [Ru(NH 3 ) 5 (N 2 )] (see figure at right), and soon many other such complexes were discovered. These complexes , in which a nitrogen molecule donates at least one lone pair of electrons to a central metal cation, illustrate how N 2 might bind to the metal(s) in nitrogenase and the catalyst for the Haber process : these processes involving dinitrogen activation are vitally important in biology and in
417-738: A pure element . In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the same atomic number, or number of protons . Nuclear scientists, however, define a pure element as one that consists of only one isotope. For example, a copper wire is 99.99% chemically pure if 99.99% of its atoms are copper, with 29 protons each. However it is not isotopically pure since ordinary copper consists of two stable isotopes, 69% Cu and 31% Cu, with different numbers of neutrons. However, pure gold would be both chemically and isotopically pure, since ordinary gold consists only of one isotope, Au. Atoms of chemically pure elements may bond to each other chemically in more than one way, allowing
556-727: A 1917 N-class coastal defense submarine of the United States Navy Huanghai N2 , a Chinese pickup truck Other uses in science and technology [ edit ] N2 diagram , in systems engineering, a function-to-function data interchange DSC-N2 , a 2006 Sony Cyber-shot series digital camera Transit [ edit ] For transportation technology, see § Transportation technology . Several roads; see List of N2 roads N2 (Long Island bus) London Buses route N2 South East Airlines (IATA airline designator) Kabo Air (IATA airline designator) Carretera Nacional N-II , former name for
695-473: A bridging ligand, donating all three electron pairs from the triple bond ( μ 3 -N 2 ). A few complexes feature multiple N 2 ligands and some feature N 2 bonded in multiple ways. Since N 2 is isoelectronic with carbon monoxide (CO) and acetylene (C 2 H 2 ), the bonding in dinitrogen complexes is closely allied to that in carbonyl compounds, although N 2 is a weaker σ -donor and π -acceptor than CO. Theoretical studies show that σ donation
834-549: A considerable amount of time. (See element naming controversy ). Precursors of such controversies involved the nationalistic namings of elements in the late 19th century. For example, lutetium was named in reference to Paris, France. The Germans were reluctant to relinquish naming rights to the French, often calling it cassiopeium . Similarly, the British discoverer of niobium originally named it columbium , in reference to
973-477: A different element in nuclear reactions , which change an atom's atomic number. Historically, the term "chemical element" meant a substance that cannot be broken down into constituent substances by chemical reactions, and for most practical purposes this definition still has validity. There was some controversy in the 1920s over whether isotopes deserved to be recognized as separate elements if they could be separated by chemical means. The term "(chemical) element"
1112-426: A dilute gas it is less dangerous and is thus used industrially to bleach and sterilise flour. Nitrogen tribromide (NBr 3 ), first prepared in 1975, is a deep red, temperature-sensitive, volatile solid that is explosive even at −100 °C. Nitrogen triiodide (NI 3 ) is still more unstable and was only prepared in 1990. Its adduct with ammonia, which was known earlier, is very shock-sensitive: it can be set off by
1251-652: A few decay products, to have been differentiated from other elements. Most recently, the synthesis of element 118 (since named oganesson ) was reported in October 2006, and the synthesis of element 117 ( tennessine ) was reported in April 2010. Of these 118 elements, 94 occur naturally on Earth. Six of these occur in extreme trace quantities: technetium , atomic number 43; promethium , number 61; astatine , number 85; francium , number 87; neptunium , number 93; and plutonium , number 94. These 94 elements have been detected in
1390-529: A few elements, such as silver and gold , are found uncombined as relatively pure native element minerals . Nearly all other naturally occurring elements occur in the Earth as compounds or mixtures. Air is mostly a mixture of molecular nitrogen and oxygen , though it does contain compounds including carbon dioxide and water , as well as atomic argon , a noble gas which is chemically inert and therefore does not undergo chemical reactions. The history of
1529-498: A liquid, it is a very good solvent with a high heat of vaporisation (enabling it to be used in vacuum flasks), that also has a low viscosity and electrical conductivity and high dielectric constant , and is less dense than water. However, the hydrogen bonding in NH 3 is weaker than that in H 2 O due to the lower electronegativity of nitrogen compared to oxygen and the presence of only one lone pair in NH 3 rather than two in H 2 O. It
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#17327811752281668-483: A long time, sources of nitrogen compounds were limited. Natural sources originated either from biology or deposits of nitrates produced by atmospheric reactions. Nitrogen fixation by industrial processes like the Frank–Caro process (1895–1899) and Haber–Bosch process (1908–1913) eased this shortage of nitrogen compounds, to the extent that half of global food production now relies on synthetic nitrogen fertilisers. At
1807-494: A preference for forming multiple bonds, typically with carbon, oxygen, or other nitrogen atoms, through p π –p π interactions. Thus, for example, nitrogen occurs as diatomic molecules and therefore has very much lower melting (−210 °C) and boiling points (−196 °C) than the rest of its group, as the N 2 molecules are only held together by weak van der Waals interactions and there are very few electrons available to create significant instantaneous dipoles. This
1946-500: A pressure of 1 bar and a given temperature (typically at 298.15K). However, for phosphorus, the reference state is white phosphorus even though it is not the most stable allotrope, and the reference state for carbon is graphite, because the structure of graphite is more stable than that of the other allotropes. In thermochemistry , an element is defined to have an enthalpy of formation of zero in its reference state. Several kinds of descriptive categorizations can be applied broadly to
2085-483: A pressure of one atmosphere, are commonly used in characterizing the various elements. While known for most elements, either or both of these measurements is still undetermined for some of the radioactive elements available in only tiny quantities. Since helium remains a liquid even at absolute zero at atmospheric pressure, it has only a boiling point, and not a melting point, in conventional presentations. The density at selected standard temperature and pressure (STP)
2224-591: A problem which is only exacerbated by its low gyromagnetic ratio , (only 10.14% that of H). As a result, the signal-to-noise ratio for H is about 300 times as much as that for N at the same magnetic field strength. This may be somewhat alleviated by isotopic enrichment of N by chemical exchange or fractional distillation. N-enriched compounds have the advantage that under standard conditions, they do not undergo chemical exchange of their nitrogen atoms with atmospheric nitrogen, unlike compounds with labelled hydrogen , carbon, and oxygen isotopes that must be kept away from
2363-470: A promising ceramic if not for the difficulty of working with and sintering it. In particular, the group 13 nitrides, most of which are promising semiconductors , are isoelectronic with graphite, diamond, and silicon carbide and have similar structures: their bonding changes from covalent to partially ionic to metallic as the group is descended. In particular, since the B–N unit is isoelectronic to C–C, and carbon
2502-463: A significant dynamic surface coverage on Pluto and outer moons of the Solar System such as Triton . Even at the low temperatures of solid nitrogen it is fairly volatile and can sublime to form an atmosphere, or condense back into nitrogen frost. It is very weak and flows in the form of glaciers, and on Triton geysers of nitrogen gas come from the polar ice cap region. The first example of
2641-456: A small group, (the metalloids ), having intermediate properties and often behaving as semiconductors . A more refined classification is often shown in colored presentations of the periodic table. This system restricts the terms "metal" and "nonmetal" to only certain of the more broadly defined metals and nonmetals, adding additional terms for certain sets of the more broadly viewed metals and nonmetals. The version of this classification used in
2780-606: A very high energy density, that could be used as powerful propellants or explosives. Under extremely high pressures (1.1 million atm ) and high temperatures (2000 K), as produced in a diamond anvil cell , nitrogen polymerises into the single-bonded cubic gauche crystal structure. This structure is similar to that of diamond , and both have extremely strong covalent bonds , resulting in its nickname "nitrogen diamond". At atmospheric pressure , molecular nitrogen condenses ( liquefies ) at 77 K (−195.79 ° C ) and freezes at 63 K (−210.01 °C) into
2919-445: A video sharing website Science and technology [ edit ] Biology and medicine [ edit ] N200 (neuroscience) , an event-related potential (ERP) component in the 200-300 ms poststimulus range A non-small cell lung carcinoma staging code for Metastasis to ipsilateral mediastinal or subcarinal lymph nodes A para formaldehyde-based filling material for root canals , also called Sargenti paste A strain of
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#17327811752283058-474: A whole number. For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than ~1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are naturally present in a sample of that element. Chemists and nuclear scientists have different definitions of
3197-465: Is oxatetrazole (N 4 O), an aromatic ring. Nitrous oxide (N 2 O), better known as laughing gas, is made by thermal decomposition of molten ammonium nitrate at 250 °C. This is a redox reaction and thus nitric oxide and nitrogen are also produced as byproducts. It is mostly used as a propellant and aerating agent for sprayed canned whipped cream , and was formerly commonly used as an anaesthetic. Despite appearances, it cannot be considered to be
3336-404: Is 10 (for tin , element 50). The mass number of an element, A , is the number of nucleons (protons and neutrons) in the atomic nucleus. Different isotopes of a given element are distinguished by their mass number, which is written as a superscript on the left hand side of the chemical symbol (e.g., U). The mass number is always an integer and has units of "nucleons". Thus, magnesium-24 (24
3475-439: Is ONF 3 , which has aroused interest due to the short N–O distance implying partial double bonding and the highly polar and long N–F bond. Tetrafluorohydrazine, unlike hydrazine itself, can dissociate at room temperature and above to give the radical NF 2 •. Fluorine azide (FN 3 ) is very explosive and thermally unstable. Dinitrogen difluoride (N 2 F 2 ) exists as thermally interconvertible cis and trans isomers, and
3614-606: Is a mixture of C (about 98.9%), C (about 1.1%) and about 1 atom per trillion of C. Most (54 of 94) naturally occurring elements have more than one stable isotope. Except for the isotopes of hydrogen (which differ greatly from each other in relative mass—enough to cause chemical effects), the isotopes of a given element are chemically nearly indistinguishable. All elements have radioactive isotopes (radioisotopes); most of these radioisotopes do not occur naturally. Radioisotopes typically decay into other elements via alpha decay , beta decay , or inverse beta decay ; some isotopes of
3753-406: Is a dimensionless number equal to the atomic mass divided by the atomic mass constant , which equals 1 Da. In general, the mass number of a given nuclide differs in value slightly from its relative atomic mass, since the mass of each proton and neutron is not exactly 1 Da; since the electrons contribute a lesser share to the atomic mass as neutron number exceeds proton number; and because of
3892-419: Is a fuming, colourless liquid that smells similar to ammonia. Its physical properties are very similar to those of water (melting point 2.0 °C, boiling point 113.5 °C, density 1.00 g/cm ). Despite it being an endothermic compound, it is kinetically stable. It burns quickly and completely in air very exothermically to give nitrogen and water vapour. It is a very useful and versatile reducing agent and
4031-491: Is a more important factor allowing the formation of the M–N bond than π back-donation, which mostly only weakens the N–N bond, and end-on ( η ) donation is more readily accomplished than side-on ( η ) donation. Today, dinitrogen complexes are known for almost all the transition metals , accounting for several hundred compounds. They are normally prepared by three methods: Occasionally
4170-467: Is a weak base in aqueous solution ( p K b 4.74); its conjugate acid is ammonium , NH 4 . It can also act as an extremely weak acid, losing a proton to produce the amide anion, NH 2 . It thus undergoes self-dissociation, similar to water, to produce ammonium and amide. Ammonia burns in air or oxygen, though not readily, to produce nitrogen gas; it burns in fluorine with a greenish-yellow flame to give nitrogen trifluoride . Reactions with
4309-401: Is a weak diprotic acid with the structure HON=NOH (p K a1 6.9, p K a2 11.6). Acidic solutions are quite stable but above pH 4 base-catalysed decomposition occurs via [HONNO] to nitrous oxide and the hydroxide anion. Hyponitrites (involving the N 2 O 2 anion) are stable to reducing agents and more commonly act as reducing agents themselves. They are an intermediate step in
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4448-399: Is a weaker base than ammonia. It is also commonly used as a rocket fuel. Hydrazine is generally made by reaction of ammonia with alkaline sodium hypochlorite in the presence of gelatin or glue: (The attacks by hydroxide and ammonia may be reversed, thus passing through the intermediate NHCl instead.) The reason for adding gelatin is that it removes metal ions such as Cu that catalyses
4587-612: Is also evidence for the asymmetric red dimer O=N–O=N when nitric oxide is condensed with polar molecules. It reacts with oxygen to give brown nitrogen dioxide and with halogens to give nitrosyl halides. It also reacts with transition metal compounds to give nitrosyl complexes, most of which are deeply coloured. Blue dinitrogen trioxide (N 2 O 3 ) is only available as a solid because it rapidly dissociates above its melting point to give nitric oxide, nitrogen dioxide (NO 2 ), and dinitrogen tetroxide (N 2 O 4 ). The latter two compounds are somewhat difficult to study individually because of
4726-812: Is an ongoing area of scientific study. The lightest elements are hydrogen and helium , both created by Big Bang nucleosynthesis in the first 20 minutes of the universe in a ratio of around 3:1 by mass (or 12:1 by number of atoms), along with tiny traces of the next two elements, lithium and beryllium . Almost all other elements found in nature were made by various natural methods of nucleosynthesis . On Earth, small amounts of new atoms are naturally produced in nucleogenic reactions, or in cosmogenic processes, such as cosmic ray spallation . New atoms are also naturally produced on Earth as radiogenic daughter isotopes of ongoing radioactive decay processes such as alpha decay , beta decay , spontaneous fission , cluster decay , and other rarer modes of decay. Of
4865-460: Is based on a Latin or other traditional word, for example adopting "gold" rather than "aurum" as the name for the 79th element (Au). IUPAC prefers the British spellings " aluminium " and "caesium" over the U.S. spellings "aluminum" and "cesium", and the U.S. "sulfur" over British "sulphur". However, elements that are practical to sell in bulk in many countries often still have locally used national names, and countries whose national language does not use
5004-464: Is common, where the nitrito form is usually less stable. Chemical element A chemical element is a chemical substance whose atoms all have the same number of protons . The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8, meaning each oxygen atom has 8 protons in its nucleus. Atoms of the same element can have different numbers of neutrons in their nuclei, known as isotopes of
5143-415: Is different from Wikidata All article disambiguation pages All disambiguation pages Nitrogen#Allotropes Nitrogen is a chemical element ; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table , often called the pnictogens . It is a common element in the universe , estimated at seventh in total abundance in
5282-404: Is essentially intermediate in size between boron and nitrogen, much of organic chemistry finds an echo in boron–nitrogen chemistry, such as in borazine ("inorganic benzene "). Nevertheless, the analogy is not exact due to the ease of nucleophilic attack at boron due to its deficiency in electrons, which is not possible in a wholly carbon-containing ring. The largest category of nitrides are
5421-515: Is known. Industrially, ammonia (NH 3 ) is the most important compound of nitrogen and is prepared in larger amounts than any other compound because it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilisers. It is a colourless alkaline gas with a characteristic pungent smell. The presence of hydrogen bonding has very significant effects on ammonia, conferring on it its high melting (−78 °C) and boiling (−33 °C) points. As
5560-434: Is mildly toxic in concentrations above 100 mg/kg, but small amounts are often used to cure meat and as a preservative to avoid bacterial spoilage. It is also used to synthesise hydroxylamine and to diazotise primary aromatic amines as follows: Nitrite is also a common ligand that can coordinate in five ways. The most common are nitro (bonded from the nitrogen) and nitrito (bonded from an oxygen). Nitro-nitrito isomerism
5699-629: Is mostly unreactive at room temperature, but it will nevertheless react with lithium metal and some transition metal complexes. This is due to its bonding, which is unique among the diatomic elements at standard conditions in that it has an N≡N triple bond . Triple bonds have short bond lengths (in this case, 109.76 pm) and high dissociation energies (in this case, 945.41 kJ/mol), and are thus very strong, explaining dinitrogen's low level of chemical reactivity. Other nitrogen oligomers and polymers may be possible. If they could be synthesised, they may have potential applications as materials with
N2 - Misplaced Pages Continue
5838-489: Is much more common, making up 99.634% of natural nitrogen, and the second (which is slightly heavier) makes up the remaining 0.366%. This leads to an atomic weight of around 14.007 u. Both of these stable isotopes are produced in the CNO cycle in stars , but N is more common as its proton capture is the rate-limiting step. N is one of the five stable odd–odd nuclides (a nuclide having an odd number of protons and neutrons);
5977-682: Is not possible for its vertical neighbours; thus, the nitrogen oxides , nitrites , nitrates , nitro- , nitroso -, azo -, and diazo -compounds, azides , cyanates , thiocyanates , and imino -derivatives find no echo with phosphorus, arsenic, antimony, or bismuth. By the same token, however, the complexity of the phosphorus oxoacids finds no echo with nitrogen. Setting aside their differences, nitrogen and phosphorus form an extensive series of compounds with one another; these have chain, ring, and cage structures. Table of thermal and physical properties of nitrogen (N 2 ) at atmospheric pressure: Nitrogen has two stable isotopes : N and N. The first
6116-660: Is of interest for the preparation of explosives. It is a deliquescent , colourless crystalline solid that is sensitive to light. In the solid state it is ionic with structure [NO 2 ] [NO 3 ] ; as a gas and in solution it is molecular O 2 N–O–NO 2 . Hydration to nitric acid comes readily, as does analogous reaction with hydrogen peroxide giving peroxonitric acid (HOONO 2 ). It is a violent oxidising agent. Gaseous dinitrogen pentoxide decomposes as follows: Many nitrogen oxoacids are known, though most of them are unstable as pure compounds and are known only as aqueous solutions or as salts. Hyponitrous acid (H 2 N 2 O 2 )
6255-436: Is often used in characterizing the elements. Density is often expressed in grams per cubic centimetre (g/cm ). Since several elements are gases at commonly encountered temperatures, their densities are usually stated for their gaseous forms; when liquefied or solidified, the gaseous elements have densities similar to those of the other elements. When an element has allotropes with different densities, one representative allotrope
6394-521: Is prepared by passing an electric discharge through nitrogen gas at 0.1–2 mmHg, which produces atomic nitrogen along with a peach-yellow emission that fades slowly as an afterglow for several minutes even after the discharge terminates. Given the great reactivity of atomic nitrogen, elemental nitrogen usually occurs as molecular N 2 , dinitrogen. This molecule is a colourless, odourless, and tasteless diamagnetic gas at standard conditions: it melts at −210 °C and boils at −196 °C. Dinitrogen
6533-443: Is produced from O (in water) via an (n,p) reaction , in which the O atom captures a neutron and expels a proton. It has a short half-life of about 7.1 s, but its decay back to O produces high-energy gamma radiation (5 to 7 MeV). Because of this, access to the primary coolant piping in a pressurised water reactor must be restricted during reactor power operation. It is a sensitive and immediate indicator of leaks from
6672-474: Is significant. It is a weak acid with p K a 3.35 at 18 °C. They may be titrimetrically analysed by their oxidation to nitrate by permanganate . They are readily reduced to nitrous oxide and nitric oxide by sulfur dioxide , to hyponitrous acid with tin (II), and to ammonia with hydrogen sulfide . Salts of hydrazinium N 2 H 5 react with nitrous acid to produce azides which further react to give nitrous oxide and nitrogen. Sodium nitrite
6811-482: Is similar to that in nitrogen, but one extra electron is added to a π * antibonding orbital and thus the bond order has been reduced to approximately 2.5; hence dimerisation to O=N–N=O is unfavourable except below the boiling point (where the cis isomer is more stable) because it does not actually increase the total bond order and because the unpaired electron is delocalised across the NO molecule, granting it stability. There
6950-404: Is smaller than those of boron (84 pm) and carbon (76 pm), while it is larger than those of oxygen (66 pm) and fluorine (57 pm). The nitride anion, N , is much larger at 146 pm, similar to that of the oxide (O : 140 pm) and fluoride (F : 133 pm) anions. The first three ionisation energies of nitrogen are 1.402, 2.856, and 4.577 MJ·mol , and the sum of
7089-426: Is the mass number) is an atom with 24 nucleons (12 protons and 12 neutrons). Whereas the mass number simply counts the total number of neutrons and protons and is thus an integer, the atomic mass of a particular isotope (or "nuclide") of the element is the mass of a single atom of that isotope, and is typically expressed in daltons (symbol: Da), or universal atomic mass units (symbol: u). Its relative atomic mass
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#17327811752287228-523: Is the most important nitrogen radioisotope, being relatively long-lived enough to use in positron emission tomography (PET), although its half-life is still short and thus it must be produced at the venue of the PET, for example in a cyclotron via proton bombardment of O producing N and an alpha particle . The radioisotope N is the dominant radionuclide in the coolant of pressurised water reactors or boiling water reactors during normal operation. It
7367-400: Is the simplest stable molecule with an odd number of electrons. In mammals, including humans, it is an important cellular signalling molecule involved in many physiological and pathological processes. It is formed by catalytic oxidation of ammonia. It is a colourless paramagnetic gas that, being thermodynamically unstable, decomposes to nitrogen and oxygen gas at 1100–1200 °C. Its bonding
7506-476: Is the strongest π donor known among ligands (the second-strongest is O ). Nitrido complexes are generally made by the thermal decomposition of azides or by deprotonating ammonia, and they usually involve a terminal {≡N} group. The linear azide anion ( N 3 ), being isoelectronic with nitrous oxide , carbon dioxide , and cyanate , forms many coordination complexes. Further catenation is rare, although N 4 (isoelectronic with carbonate and nitrate )
7645-640: Is thermodynamically stable, and most readily produced by the electrolysis of molten ammonium fluoride dissolved in anhydrous hydrogen fluoride . Like carbon tetrafluoride , it is not at all reactive and is stable in water or dilute aqueous acids or alkalis. Only when heated does it act as a fluorinating agent, and it reacts with copper , arsenic, antimony, and bismuth on contact at high temperatures to give tetrafluorohydrazine (N 2 F 4 ). The cations NF 4 and N 2 F 3 are also known (the latter from reacting tetrafluorohydrazine with strong fluoride-acceptors such as arsenic pentafluoride ), as
7784-532: Is typically selected in summary presentations, while densities for each allotrope can be stated where more detail is provided. For example, the three familiar allotropes of carbon ( amorphous carbon , graphite , and diamond ) have densities of 1.8–2.1, 2.267, and 3.515 g/cm , respectively. The elements studied to date as solid samples have eight kinds of crystal structures : cubic , body-centered cubic , face-centered cubic, hexagonal , monoclinic , orthorhombic , rhombohedral , and tetragonal . For some of
7923-417: Is used in two different but closely related meanings: it can mean a chemical substance consisting of a single kind of atoms, or it can mean that kind of atoms as a component of various chemical substances. For example, molecules of water (H 2 O) contain atoms of hydrogen (H) and oxygen (O), so water can be said as a compound consisting of the elements hydrogen (H) and oxygen (O) even though it does not contain
8062-506: Is usually produced from air by pressure swing adsorption technology. About 2/3 of commercially produced elemental nitrogen is used as an inert (oxygen-free) gas for commercial uses such as food packaging, and much of the rest is used as liquid nitrogen in cryogenic applications. Many industrially important compounds, such as ammonia , nitric acid, organic nitrates ( propellants and explosives ), and cyanides , contain nitrogen. The extremely strong triple bond in elemental nitrogen (N≡N),
8201-429: Is very strong; fullerenes , which have nearly spherical shapes; and carbon nanotubes , which are tubes with a hexagonal structure (even these may differ from each other in electrical properties). The ability of an element to exist in one of many structural forms is known as 'allotropy'. The reference state of an element is defined by convention, usually as the thermodynamically most stable allotrope and physical state at
8340-590: Is widely used. For example, the French chemical terminology distinguishes élément chimique (kind of atoms) and corps simple (chemical substance consisting of a single kind of atoms); the Russian chemical terminology distinguishes химический элемент and простое вещество . Almost all baryonic matter in the universe is composed of elements (among rare exceptions are neutron stars ). When different elements undergo chemical reactions, atoms are rearranged into new compounds held together by chemical bonds . Only
8479-555: The Caenorhabditis elegans var. Bristol model worm Transportation technology [ edit ] N 2 , gauges that monitor the power turbine section in a jet engine N-2 , an Armenian multiple rocket launcher system N-2 rocket , a 1981 Japanese derivative of the American Delta rocket A type of large goods vehicle GNR Class N2 , a 1920 British 0-6-2T steam locomotive class USS N-2 (SS-54) ,
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#17327811752288618-512: The Greek word άζωτικός (azotikos), "no life", due to it being asphyxiant . In an atmosphere of pure nitrogen, animals died and flames were extinguished. Though Lavoisier's name was not accepted in English since it was pointed out that all gases but oxygen are either asphyxiant or outright toxic, it is used in many languages (French, Italian, Portuguese, Polish, Russian, Albanian, Turkish, etc.;
8757-489: The International Union of Pure and Applied Chemistry (IUPAC) had recognized a total of 118 elements. The first 94 occur naturally on Earth , and the remaining 24 are synthetic elements produced in nuclear reactions. Save for unstable radioactive elements (radioelements) which decay quickly, nearly all elements are available industrially in varying amounts. The discovery and synthesis of further new elements
8896-583: The Latin alphabet are likely to use the IUPAC element names. According to IUPAC, element names are not proper nouns; therefore, the full name of an element is not capitalized in English, even if derived from a proper noun , as in californium and einsteinium . Isotope names are also uncapitalized if written out, e.g., carbon-12 or uranium-235 . Chemical element symbols (such as Cf for californium and Es for einsteinium), are always capitalized (see below). In
9035-715: The Milky Way and the Solar System . At standard temperature and pressure , two atoms of the element bond to form N 2 , a colourless and odourless diatomic gas . N 2 forms about 78% of Earth's atmosphere , making it the most abundant chemical species in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772 and independently by Carl Wilhelm Scheele and Henry Cavendish at about
9174-435: The anhydride of hyponitrous acid (H 2 N 2 O 2 ) because that acid is not produced by the dissolution of nitrous oxide in water. It is rather unreactive (not reacting with the halogens, the alkali metals, or ozone at room temperature, although reactivity increases upon heating) and has the unsymmetrical structure N–N–O (N≡N O ↔ N=N =O): above 600 °C it dissociates by breaking the weaker N–O bond. Nitric oxide (NO)
9313-476: The eutrophication of water systems. Apart from its use in fertilisers and energy stores, nitrogen is a constituent of organic compounds as diverse as aramids used in high-strength fabric and cyanoacrylate used in superglue . Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins ), in the nucleic acids ( DNA and RNA ) and in the energy transfer molecule adenosine triphosphate . The human body contains about 3% nitrogen by mass,
9452-423: The kinetic isotope effect is significant). Thus, all carbon isotopes have nearly identical chemical properties because they all have six electrons, even though they may have 6 to 8 neutrons. That is why atomic number, rather than mass number or atomic weight , is considered the identifying characteristic of an element. The symbol for atomic number is Z . Isotopes are atoms of the same element (that is, with
9591-405: The nuclear binding energy and electron binding energy. For example, the atomic mass of chlorine-35 to five significant digits is 34.969 Da and that of chlorine-37 is 36.966 Da. However, the relative atomic mass of each isotope is quite close to its mass number (always within 1%). The only isotope whose atomic mass is exactly a natural number is C, which has a mass of 12 Da; because
9730-566: The 2s and 2p orbitals, three of which (the p-electrons) are unpaired. It has one of the highest electronegativities among the elements (3.04 on the Pauling scale), exceeded only by chlorine (3.16), oxygen (3.44), and fluorine (3.98). (The light noble gases , helium , neon , and argon , would presumably also be more electronegative, and in fact are on the Allen scale.) Following periodic trends, its single-bond covalent radius of 71 pm
9869-638: The 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope (except for technetium , element 43 and promethium , element 61, which have no stable isotopes). Isotopes considered stable are those for which no radioactive decay has yet been observed. Elements with atomic numbers 83 through 94 are unstable to the point that radioactive decay of all isotopes can be detected. Some of these elements, notably bismuth (atomic number 83), thorium (atomic number 90), and uranium (atomic number 92), have one or more isotopes with half-lives long enough to survive as remnants of
10008-580: The French nitrogène , coined in 1790 by French chemist Jean-Antoine Chaptal (1756–1832), from the French nitre ( potassium nitrate , also called saltpetre ) and the French suffix -gène , "producing", from the Greek -γενής (-genes, "begotten"). Chaptal's meaning was that nitrogen is the essential part of nitric acid , which in turn was produced from nitre . In earlier times, nitre had been confused with Egyptian "natron" ( sodium carbonate ) – called νίτρον (nitron) in Greek ;– which, despite
10147-487: The French, Italians, Greeks, Portuguese and Poles prefer "azote/azot/azoto" (from roots meaning "no life") for "nitrogen". For purposes of international communication and trade, the official names of the chemical elements both ancient and more recently recognized are decided by the International Union of Pure and Applied Chemistry (IUPAC), which has decided on a sort of international English language, drawing on traditional English names even when an element's chemical symbol
10286-535: The German Stickstoff similarly refers to the same characteristic, viz. ersticken "to choke or suffocate") and still remains in English in the common names of many nitrogen compounds, such as hydrazine and compounds of the azide ion. Finally, it led to the name " pnictogens " for the group headed by nitrogen, from the Greek πνίγειν "to choke". The English word nitrogen (1794) entered the language from
10425-744: The Middle Ages. Alchemists knew nitric acid as aqua fortis (strong water), as well as other nitrogen compounds such as ammonium salts and nitrate salts. The mixture of nitric and hydrochloric acids was known as aqua regia (royal water), celebrated for its ability to dissolve gold , the king of metals. The discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air . Though he did not recognise it as an entirely different chemical substance, he clearly distinguished it from Joseph Black's "fixed air" , or carbon dioxide. The fact that there
10564-860: The N anion, although charge separation is not actually complete even for these highly electropositive elements. However, the alkali metal azides NaN 3 and KN 3 , featuring the linear N 3 anion, are well-known, as are Sr(N 3 ) 2 and Ba(N 3 ) 2 . Azides of the B-subgroup metals (those in groups 11 through 16 ) are much less ionic, have more complicated structures, and detonate readily when shocked. Many covalent binary nitrides are known. Examples include cyanogen ((CN) 2 ), triphosphorus pentanitride (P 3 N 5 ), disulfur dinitride (S 2 N 2 ), and tetrasulfur tetranitride (S 4 N 4 ). The essentially covalent silicon nitride (Si 3 N 4 ) and germanium nitride (Ge 3 N 4 ) are also known: silicon nitride, in particular, would make
10703-450: The N≡N bond may be formed directly within a metal complex, for example by directly reacting coordinated ammonia (NH 3 ) with nitrous acid (HNO 2 ), but this is not generally applicable. Most dinitrogen complexes have colours within the range white-yellow-orange-red-brown; a few exceptions are known, such as the blue [{Ti( η -C 5 H 5 ) 2 } 2 -(N 2 )]. Nitrogen bonds to almost all
10842-751: The Route Nacional from Madrid to Barcelona and France Other uses [ edit ] A United States Navy term for a senior military intelligence officer N2 Gateway , a housing project along the N2 freeway in Cape Town, South Africa N2, a postcode district in the N postcode area The fourth level in the Japanese Language Proficiency Test See also [ edit ] NO2 (disambiguation) NII (disambiguation) [REDACTED] Topics referred to by
10981-418: The ability to form coordination complexes by donating its lone pairs of electrons. There are some parallels between the chemistry of ammonia NH 3 and water H 2 O. For example, the capacity of both compounds to be protonated to give NH 4 and H 3 O or deprotonated to give NH 2 and OH , with all of these able to be isolated in solid compounds. Nitrogen shares with both its horizontal neighbours
11120-417: The atmosphere. The N: N ratio is commonly used in stable isotope analysis in the fields of geochemistry , hydrology , paleoclimatology and paleoceanography , where it is called δ N . Of the thirteen other isotopes produced synthetically, ranging from N to N, N has a half-life of ten minutes and the remaining isotopes have half-lives less than eight seconds. Given the half-life difference, N
11259-487: The atomic masses of the elements (their atomic weights or atomic masses) do not always increase monotonically with their atomic numbers. The naming of various substances now known as elements precedes the atomic theory of matter, as names were given locally by various cultures to various minerals, metals, compounds, alloys, mixtures, and other materials, though at the time it was not known which chemicals were elements and which compounds. As they were identified as elements,
11398-435: The beta hexagonal close-packed crystal allotropic form. Below 35.4 K (−237.6 °C) nitrogen assumes the cubic crystal allotropic form (called the alpha phase). Liquid nitrogen , a colourless fluid resembling water in appearance, but with 80.8% of the density (the density of liquid nitrogen at its boiling point is 0.808 g/mL), is a common cryogen . Solid nitrogen has many crystalline modifications. It forms
11537-413: The chemical substances (di)hydrogen (H 2 ) and (di)oxygen (O 2 ), as H 2 O molecules are different from H 2 and O 2 molecules. For the meaning "chemical substance consisting of a single kind of atoms", the terms "elementary substance" and "simple substance" have been suggested, but they have not gained much acceptance in English chemical literature, whereas in some other languages their equivalent
11676-416: The conjugate acid of the azide anion, and is similarly analogous to the hydrohalic acids . All four simple nitrogen trihalides are known. A few mixed halides and hydrohalides are known, but are mostly unstable; examples include NClF 2 , NCl 2 F, NBrF 2 , NF 2 H, NFH 2 , NCl 2 H , and NClH 2 . Nitrogen trifluoride (NF 3 , first prepared in 1928) is a colourless and odourless gas that
11815-555: The continuity of bonding types instead of the discrete and separate types that it implies. They are normally prepared by directly reacting a metal with nitrogen or ammonia (sometimes after heating), or by thermal decomposition of metal amides: Many variants on these processes are possible. The most ionic of these nitrides are those of the alkali metals and alkaline earth metals , Li 3 N (Na, K, Rb, and Cs do not form stable nitrides for steric reasons) and M 3 N 2 (M = Be, Mg, Ca, Sr, Ba). These can formally be thought of as salts of
11954-408: The dalton is defined as 1/12 of the mass of a free neutral carbon-12 atom in the ground state. The standard atomic weight (commonly called "atomic weight") of an element is the average of the atomic masses of all the chemical element's isotopes as found in a particular environment, weighted by isotopic abundance, relative to the atomic mass unit. This number may be a fraction that is not close to
12093-417: The destruction of hydrazine by reaction with monochloramine (NH 2 Cl) to produce ammonium chloride and nitrogen. Hydrogen azide (HN 3 ) was first produced in 1890 by the oxidation of aqueous hydrazine by nitrous acid. It is very explosive and even dilute solutions can be dangerous. It has a disagreeable and irritating smell and is a potentially lethal (but not cumulative) poison. It may be considered
12232-416: The discovery and use of elements began with early human societies that discovered native minerals like carbon , sulfur , copper and gold (though the modern concept of an element was not yet understood). Attempts to classify materials such as these resulted in the concepts of classical elements , alchemy , and similar theories throughout history. Much of the modern understanding of elements developed from
12371-526: The element. Two or more atoms can combine to form molecules . Some elements are formed from molecules of identical atoms , e. g. atoms of hydrogen (H) form diatomic molecules (H 2 ). Chemical compounds are substances made of atoms of different elements; they can have molecular or non-molecular structure. Mixtures are materials containing different chemical substances; that means (in case of molecular substances) that they contain different types of molecules. Atoms of one element can be transformed into atoms of
12510-406: The elements are available by name, atomic number, density, melting point, boiling point and chemical symbol , as well as ionization energy . The nuclides of stable and radioactive elements are also available as a list of nuclides , sorted by length of half-life for those that are unstable. One of the most convenient, and certainly the most traditional presentation of the elements, is in the form of
12649-470: The elements are often summarized using the periodic table, which powerfully and elegantly organizes the elements by increasing atomic number into rows ( "periods" ) in which the columns ( "groups" ) share recurring ("periodic") physical and chemical properties. The table contains 118 confirmed elements as of 2021. Although earlier precursors to this presentation exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869, who intended
12788-480: The elements can be uniquely sequenced by atomic number, conventionally from lowest to highest (as in a periodic table), sets of elements are sometimes specified by such notation as "through", "beyond", or "from ... through", as in "through iron", "beyond uranium", or "from lanthanum through lutetium". The terms "light" and "heavy" are sometimes also used informally to indicate relative atomic numbers (not densities), as in "lighter than carbon" or "heavier than lead", though
12927-734: The elements in the periodic table except the first two noble gases , helium and neon , and some of the very short-lived elements after bismuth , creating an immense variety of binary compounds with varying properties and applications. Many binary compounds are known: with the exception of the nitrogen hydrides, oxides, and fluorides, these are typically called nitrides . Many stoichiometric phases are usually present for most elements (e.g. MnN, Mn 6 N 5 , Mn 3 N 2 , Mn 2 N, Mn 4 N, and Mn x N for 9.2 < x < 25.3). They may be classified as "salt-like" (mostly ionic), covalent, "diamond-like", and metallic (or interstitial ), although this classification has limitations generally stemming from
13066-413: The elements without any stable isotopes are technetium (atomic number 43), promethium (atomic number 61), and all observed elements with atomic number greater than 82. Of the 80 elements with at least one stable isotope, 26 have only one stable isotope. The mean number of stable isotopes for the 80 stable elements is 3.1 stable isotopes per element. The largest number of stable isotopes for a single element
13205-474: The elements, including consideration of their general physical and chemical properties, their states of matter under familiar conditions, their melting and boiling points, their densities, their crystal structures as solids, and their origins. Several terms are commonly used to characterize the general physical and chemical properties of the chemical elements. A first distinction is between metals , which readily conduct electricity , nonmetals , which do not, and
13344-467: The equilibrium between them, although sometimes dinitrogen tetroxide can react by heterolytic fission to nitrosonium and nitrate in a medium with high dielectric constant. Nitrogen dioxide is an acrid, corrosive brown gas. Both compounds may be easily prepared by decomposing a dry metal nitrate. Both react with water to form nitric acid . Dinitrogen tetroxide is very useful for the preparation of anhydrous metal nitrates and nitrato complexes, and it became
13483-492: The existing names for anciently known elements (e.g., gold, mercury, iron) were kept in most countries. National differences emerged over the element names either for convenience, linguistic niceties, or nationalism. For example, German speakers use "Wasserstoff" (water substance) for "hydrogen", "Sauerstoff" (acid substance) for "oxygen" and "Stickstoff" (smothering substance) for "nitrogen"; English and some other languages use "sodium" for "natrium", and "potassium" for "kalium"; and
13622-630: The explosive stellar nucleosynthesis that produced the heavy metals before the formation of our Solar System . At over 1.9 × 10 years, over a billion times longer than the estimated age of the universe, bismuth-209 has the longest known alpha decay half-life of any isotope, and is almost always considered on par with the 80 stable elements. The heaviest elements (those beyond plutonium, element 94) undergo radioactive decay with half-lives so short that they are not found in nature and must be synthesized . There are now 118 known elements. In this context, "known" means observed well enough, even from just
13761-421: The first gases to be identified: N 2 O ( nitrous oxide ), NO ( nitric oxide ), N 2 O 3 ( dinitrogen trioxide ), NO 2 ( nitrogen dioxide ), N 2 O 4 ( dinitrogen tetroxide ), N 2 O 5 ( dinitrogen pentoxide ), N 4 O ( nitrosylazide ), and N(NO 2 ) 3 ( trinitramide ). All are thermally unstable towards decomposition to their elements. One other possible oxide that has not yet been synthesised
13900-529: The formation of Earth, they are certain to have completely decayed, and if present in novae, are in quantities too small to have been noted. Technetium was the first purportedly non-naturally occurring element synthesized, in 1937, though trace amounts of technetium have since been found in nature (and also the element may have been discovered naturally in 1925). This pattern of artificial production and later natural discovery has been repeated with several other radioactive naturally occurring rare elements. List of
14039-496: The fourth and fifth is 16.920 MJ·mol . Due to these very high figures, nitrogen has no simple cationic chemistry. The lack of radial nodes in the 2p subshell is directly responsible for many of the anomalous properties of the first row of the p-block , especially in nitrogen, oxygen, and fluorine. The 2p subshell is very small and has a very similar radius to the 2s shell, facilitating orbital hybridisation . It also results in very large electrostatic forces of attraction between
14178-422: The fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes the movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere. Nitrogen is a constituent of every major pharmacological drug class, including antibiotics . Many drugs are mimics or prodrugs of natural nitrogen-containing signal molecules : for example,
14317-431: The half-lives predicted for the observationally stable lead isotopes range from 10 to 10 years. Elements with atomic numbers 43, 61, and 83 through 94 are unstable enough that their radioactive decay can be detected. Three of these elements, bismuth (element 83), thorium (90), and uranium (92) have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced
14456-437: The head of group 15 in the periodic table, its chemistry shows huge differences from that of its heavier congeners phosphorus , arsenic , antimony , and bismuth . Nitrogen may be usefully compared to its horizontal neighbours' carbon and oxygen as well as its vertical neighbours in the pnictogen column, phosphorus, arsenic, antimony, and bismuth. Although each period 2 element from lithium to oxygen shows some similarities to
14595-399: The heaviest elements also undergo spontaneous fission . Isotopes that are not radioactive, are termed "stable" isotopes. All known stable isotopes occur naturally (see primordial nuclide ). The many radioisotopes that are not found in nature have been characterized after being artificially produced. Certain elements have no stable isotopes and are composed only of radioisotopes: specifically
14734-488: The heavy elements before the formation of the Solar System. For example, at over 1.9 × 10 years, over a billion times longer than the estimated age of the universe, bismuth-209 has the longest known alpha decay half-life of any isotope. The last 24 elements (those beyond plutonium, element 94) undergo radioactive decay with short half-lives and cannot be produced as daughters of longer-lived elements, and thus are not known to occur in nature at all. 1 The properties of
14873-505: The interstitial nitrides of formulae MN, M 2 N, and M 4 N (although variable composition is perfectly possible), where the small nitrogen atoms are positioned in the gaps in a metallic cubic or hexagonal close-packed lattice. They are opaque, very hard, and chemically inert, melting only at very high temperatures (generally over 2500 °C). They have a metallic lustre and conduct electricity as do metals. They hydrolyse only very slowly to give ammonia or nitrogen. The nitride anion (N )
15012-525: The name, contained no nitrate. The earliest military, industrial, and agricultural applications of nitrogen compounds used saltpetre ( sodium nitrate or potassium nitrate), most notably in gunpowder , and later as fertiliser . In 1910, Lord Rayleigh discovered that an electrical discharge in nitrogen gas produced "active nitrogen", a monatomic allotrope of nitrogen. The "whirling cloud of brilliant yellow light" produced by his apparatus reacted with mercury to produce explosive mercury nitride . For
15151-574: The nitryl halides (XNO 2 ). The first is very reactive gases that can be made by directly halogenating nitrous oxide. Nitrosyl fluoride (NOF) is colourless and a vigorous fluorinating agent. Nitrosyl chloride (NOCl) behaves in much the same way and has often been used as an ionising solvent. Nitrosyl bromide (NOBr) is red. The reactions of the nitryl halides are mostly similar: nitryl fluoride (FNO 2 ) and nitryl chloride (ClNO 2 ) are likewise reactive gases and vigorous halogenating agents. Nitrogen forms nine molecular oxides, some of which were
15290-436: The nucleus and the valence electrons in the 2s and 2p shells, resulting in very high electronegativities. Hypervalency is almost unknown in the 2p elements for the same reason, because the high electronegativity makes it difficult for a small nitrogen atom to be a central atom in an electron-rich three-center four-electron bond since it would tend to attract the electrons strongly to itself. Thus, despite nitrogen's position at
15429-410: The organic nitrates nitroglycerin and nitroprusside control blood pressure by metabolising into nitric oxide . Many notable nitrogen-containing drugs, such as the natural caffeine and morphine or the synthetic amphetamines , act on receptors of animal neurotransmitters . Nitrogen compounds have a very long history, ammonium chloride having been known to Herodotus . They were well-known by
15568-412: The other four are H , Li, B, and Ta. The relative abundance of N and N is practically constant in the atmosphere but can vary elsewhere, due to natural isotopic fractionation from biological redox reactions and the evaporation of natural ammonia or nitric acid . Biologically mediated reactions (e.g., assimilation , nitrification , and denitrification ) strongly control nitrogen dynamics in
15707-421: The other nonmetals are very complex and tend to lead to a mixture of products. Ammonia reacts on heating with metals to give nitrides. Many other binary nitrogen hydrides are known, but the most important are hydrazine (N 2 H 4 ) and hydrogen azide (HN 3 ). Although it is not a nitrogen hydride, hydroxylamine (NH 2 OH) is similar in properties and structure to ammonia and hydrazine as well. Hydrazine
15846-478: The oxidation of ammonia to nitrite, which occurs in the nitrogen cycle . Hyponitrite can act as a bridging or chelating bidentate ligand. Nitrous acid (HNO 2 ) is not known as a pure compound, but is a common component in gaseous equilibria and is an important aqueous reagent: its aqueous solutions may be made from acidifying cool aqueous nitrite ( NO 2 , bent) solutions, although already at room temperature disproportionation to nitrate and nitric oxide
15985-704: The period 3 element in the next group (from magnesium to chlorine; these are known as diagonal relationships ), their degree drops off abruptly past the boron–silicon pair. The similarities of nitrogen to sulfur are mostly limited to sulfur nitride ring compounds when both elements are the only ones present. Nitrogen does not share the proclivity of carbon for catenation . Like carbon, nitrogen tends to form ionic or metallic compounds with metals. Nitrogen forms an extensive series of nitrides with carbon, including those with chain-, graphitic- , and fullerenic -like structures. It resembles oxygen with its high electronegativity and concomitant capability for hydrogen bonding and
16124-418: The periodic table, which groups together elements with similar chemical properties (and usually also similar electronic structures). The atomic number of an element is equal to the number of protons in each atom, and defines the element. For example, all carbon atoms contain 6 protons in their atomic nucleus ; so the atomic number of carbon is 6. Carbon atoms may have different numbers of neutrons; atoms of
16263-426: The periodic tables presented here includes: actinides , alkali metals , alkaline earth metals , halogens , lanthanides , transition metals , post-transition metals , metalloids , reactive nonmetals , and noble gases . In this system, the alkali metals, alkaline earth metals, and transition metals, as well as the lanthanides and the actinides, are special groups of the metals viewed in a broader sense. Similarly,
16402-583: The primary coolant system to the secondary steam cycle and is the primary means of detection for such leaks. Atomic nitrogen, also known as active nitrogen, is highly reactive, being a triradical with three unpaired electrons. Free nitrogen atoms easily react with most elements to form nitrides, and even when two free nitrogen atoms collide to produce an excited N 2 molecule, they may release so much energy on collision with even such stable molecules as carbon dioxide and water to cause homolytic fission into radicals such as CO and O or OH and H. Atomic nitrogen
16541-522: The production of fertilisers. Dinitrogen is able to coordinate to metals in five different ways. The more well-characterised ways are the end-on M←N≡N ( η ) and M←N≡N→M ( μ , bis- η ), in which the lone pairs on the nitrogen atoms are donated to the metal cation. The less well-characterised ways involve dinitrogen donating electron pairs from the triple bond, either as a bridging ligand to two metal cations ( μ , bis- η ) or to just one ( η ). The fifth and unique method involves triple-coordination as
16680-412: The pure element to exist in multiple chemical structures ( spatial arrangements of atoms ), known as allotropes , which differ in their properties. For example, carbon can be found as diamond , which has a tetrahedral structure around each carbon atom; graphite , which has layers of carbon atoms with a hexagonal structure stacked on top of each other; graphene , which is a single layer of graphite that
16819-772: The reactive nonmetals and the noble gases are nonmetals viewed in the broader sense. In some presentations, the halogens are not distinguished, with astatine identified as a metalloid and the others identified as nonmetals. Another commonly used basic distinction among the elements is their state of matter (phase), whether solid , liquid , or gas , at standard temperature and pressure (STP). Most elements are solids at STP, while several are gases. Only bromine and mercury are liquid at 0 degrees Celsius (32 degrees Fahrenheit) and 1 atmosphere pressure; caesium and gallium are solid at that temperature, but melt at 28.4°C (83.2°F) and 29.8°C (85.6°F), respectively. Melting and boiling points , typically expressed in degrees Celsius at
16958-919: The remaining 11 elements have half lives too short for them to have been present at the beginning of the Solar System, and are therefore considered transient elements. Of these 11 transient elements, five ( polonium , radon , radium , actinium , and protactinium ) are relatively common decay products of thorium and uranium . The remaining six transient elements (technetium, promethium, astatine, francium , neptunium , and plutonium ) occur only rarely, as products of rare decay modes or nuclear reaction processes involving uranium or other heavy elements. Elements with atomic numbers 1 through 82, except 43 (technetium) and 61 (promethium), each have at least one isotope for which no radioactive decay has been observed. Observationally stable isotopes of some elements (such as tungsten and lead ), however, are predicted to be slightly radioactive with very long half-lives: for example,
17097-495: The same element having different numbers of neutrons are known as isotopes of the element. The number of protons in the nucleus also determines its electric charge , which in turn determines the number of electrons of the atom in its non-ionized state. The electrons are placed into atomic orbitals that determine the atom's chemical properties . The number of neutrons in a nucleus usually has very little effect on an element's chemical properties; except for hydrogen (for which
17236-404: The same number of protons in their nucleus), but having different numbers of neutrons . Thus, for example, there are three main isotopes of carbon. All carbon atoms have 6 protons, but they can have either 6, 7, or 8 neutrons. Since the mass numbers of these are 12, 13 and 14 respectively, said three isotopes are known as carbon-12 , carbon-13 , and carbon-14 ( C, C, and C). Natural carbon
17375-447: The same term This disambiguation page lists articles associated with the same title formed as a letter–number combination. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=N2&oldid=1172077535 " Category : Letter–number combination disambiguation pages Hidden categories: Short description
17514-583: The same time, use of the Ostwald process (1902) to produce nitrates from industrial nitrogen fixation allowed the large-scale industrial production of nitrates as feedstock in the manufacture of explosives in the World Wars of the 20th century. A nitrogen atom has seven electrons. In the ground state, they are arranged in the electron configuration 1s 2s 2p x 2p y 2p z . It, therefore, has five valence electrons in
17653-557: The same time. The name nitrogène was suggested by French chemist Jean-Antoine-Claude Chaptal in 1790 when it was found that nitrogen was present in nitric acid and nitrates . Antoine Lavoisier suggested instead the name azote , from the Ancient Greek : ἀζωτικός "no life", as it is an asphyxiant gas ; this name is used in a number of languages, and appears in the English names of some nitrogen compounds such as hydrazine , azides and azo compounds . Elemental nitrogen
17792-457: The second half of the 20th century, physics laboratories became able to produce elements with half-lives too short for an appreciable amount of them to exist at any time. These are also named by IUPAC, which generally adopts the name chosen by the discoverer. This practice can lead to the controversial question of which research group actually discovered an element, a question that delayed the naming of elements with atomic number of 104 and higher for
17931-497: The second strongest bond in any diatomic molecule after carbon monoxide (CO), dominates nitrogen chemistry. This causes difficulty for both organisms and industry in converting N 2 into useful compounds , but at the same time it means that burning, exploding, or decomposing nitrogen compounds to form nitrogen gas releases large amounts of often useful energy. Synthetically produced ammonia and nitrates are key industrial fertilisers , and fertiliser nitrates are key pollutants in
18070-451: The soil. These reactions typically result in N enrichment of the substrate and depletion of the product . The heavy isotope N was first discovered by S. M. Naudé in 1929, and soon after heavy isotopes of the neighbouring elements oxygen and carbon were discovered. It presents one of the lowest thermal neutron capture cross-sections of all isotopes. It is frequently used in nuclear magnetic resonance (NMR) spectroscopy to determine
18209-520: The storable oxidiser of choice for many rockets in both the United States and USSR by the late 1950s. This is because it is a hypergolic propellant in combination with a hydrazine -based rocket fuel and can be easily stored since it is liquid at room temperature. The thermally unstable and very reactive dinitrogen pentoxide (N 2 O 5 ) is the anhydride of nitric acid , and can be made from it by dehydration with phosphorus pentoxide . It
18348-489: The structures of nitrogen-containing molecules, due to its fractional nuclear spin of one-half, which offers advantages for NMR such as narrower line width. N, though also theoretically usable, has an integer nuclear spin of one and thus has a quadrupole moment that leads to wider and less useful spectra. N NMR nevertheless has complications not encountered in the more common H and C NMR spectroscopy. The low natural abundance of N (0.36%) significantly reduces sensitivity,
18487-496: The synthetically produced transuranic elements, available samples have been too small to determine crystal structures. Chemical elements may also be categorized by their origin on Earth, with the first 94 considered naturally occurring, while those with atomic numbers beyond 94 have only been produced artificially via human-made nuclear reactions. Of the 94 naturally occurring elements, 83 are considered primordial and either stable or weakly radioactive. The longest-lived isotopes of
18626-955: The table to illustrate recurring trends in the properties of the elements. The layout of the table has been refined and extended over time as new elements have been discovered and new theoretical models have been developed to explain chemical behavior. Use of the periodic table is now ubiquitous in chemistry, providing an extremely useful framework to classify, systematize and compare all the many different forms of chemical behavior. The table has also found wide application in physics , geology , biology , materials science , engineering , agriculture , medicine , nutrition , environmental health , and astronomy . Its principles are especially important in chemical engineering . The various chemical elements are formally identified by their unique atomic numbers, their accepted names, and their chemical symbols . The known elements have atomic numbers from 1 to 118, conventionally presented as Arabic numerals . Since
18765-420: The touch of a feather, shifting air currents, or even alpha particles . For this reason, small amounts of nitrogen triiodide are sometimes synthesised as a demonstration to high school chemistry students or as an act of "chemical magic". Chlorine azide (ClN 3 ) and bromine azide (BrN 3 ) are extremely sensitive and explosive. Two series of nitrogen oxohalides are known: the nitrosyl halides (XNO) and
18904-561: The universe at large, in the spectra of stars and also supernovae, where short-lived radioactive elements are newly being made. The first 94 elements have been detected directly on Earth as primordial nuclides present from the formation of the Solar System , or as naturally occurring fission or transmutation products of uranium and thorium. The remaining 24 heavier elements, not found today either on Earth or in astronomical spectra, have been produced artificially: all are radioactive, with short half-lives; if any of these elements were present at
19043-528: The work of Dmitri Mendeleev , a Russian chemist who published the first recognizable periodic table in 1869. This table organizes the elements by increasing atomic number into rows (" periods ") in which the columns (" groups ") share recurring ("periodic") physical and chemical properties . The periodic table summarizes various properties of the elements, allowing chemists to derive relationships between them and to make predictions about elements not yet discovered, and potential new compounds. By November 2016,
19182-412: Was a component of air that does not support combustion was clear to Rutherford, although he was not aware that it was an element. Nitrogen was also studied at about the same time by Carl Wilhelm Scheele , Henry Cavendish , and Joseph Priestley , who referred to it as burnt air or phlogisticated air . French chemist Antoine Lavoisier referred to nitrogen gas as " mephitic air " or azote , from
19321-442: Was first found as a product of the thermal decomposition of FN 3 . Nitrogen trichloride (NCl 3 ) is a dense, volatile, and explosive liquid whose physical properties are similar to those of carbon tetrachloride , although one difference is that NCl 3 is easily hydrolysed by water while CCl 4 is not. It was first synthesised in 1811 by Pierre Louis Dulong , who lost three fingers and an eye to its explosive tendencies. As
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