"Noble gas The noble gases (historically also the inert gases; sometimes referred to as aerogens) make up a group of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. The six noble gases that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn). These elements are all nonmetals. Oganesson (Og) is variously predicted to be a noble gas as well or to break the trend due to relativistic effects; its chemistry has not yet been investigated. For the first six"
"helium, neon, argon, krypton, xenon and radon. Noble gases have a full outer valence shell making them rather non-reactive species. While these elements have been described historically as completely inert, chemical compounds have been synthesized with all but neon and helium. When grouped together with the homonuclear diatomic gases such as nitrogen (N), the noble gases are called ""elemental gases"" or ""molecular gases"" to distinguish them from molecules that are also chemical compounds. Monatomic hydrogen comprises about 75% of the elemental mass of the universe. The motion of a monatomic gas is translation (electronic excitation is not important at room"
"nonmetals tend to form predominately covalent compounds with metals. Six nonmetals are categorised as noble gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn). In periodic table terms they occupy the outermost right column. They are called ""noble gases"" in light of their characteristically very low chemical reactivity. They have very similar properties, all being colorless, odorless, and nonflammable. With their closed valence shells the noble gases have feeble interatomic forces of attraction resulting in very low melting and boiling points. That is why they are all gases under standard conditions, even those"
"Noble gas compound Noble gas compounds are chemical compounds that include an element from the noble gases, group 18 of the periodic table. Although the noble gases are generally unreactive elements, many such compounds have been observed, particularly involving the element xenon. From the standpoint of chemistry, the noble gases may be divided into two groups: the relatively reactive krypton (ionisation energy 14.0 eV), xenon (12.1 eV), and radon (10.7 eV) on one side, and the very unreactive argon (15.8 eV), neon (21.6 eV), and helium (24.6 eV) on the other. Consistent with this classification, Kr, Xe, and Rn form"
"column of the periodic table, also known as group 0 or group 18. Noble gases are also called as aerogens but this nomenclature of the group is not officially accepted by the IUPAC. All of the noble gases have full outer shells with eight electrons. However, at the top of the noble gases is helium, with a shell that is full with only two electrons. The fact that their outer shells are full means they rarely react with other elements, which led to their original title of ""inert"". Because of their chemical properties, these gases are also used in the"
"with atomic masses larger than many normally solid elements. Chemically, the noble gases have relatively high ionization energies, negative electron affinities, and relatively high electronegativities. Compounds of the noble gases number less than half a thousand, with most of these occurring via oxygen or fluorine combining with either krypton, xenon or radon. The status of the period 7 congener of the noble gases, oganesson (Og), is not known—it may or may not be a noble gas. It was originally predicted to be a noble gas but may instead be a fairly reactive solid with an anomalously low first ionisation potential,"
"noble gas (atomic numbers 2, 10, 18, 36, 54, 86, and 118): as any further electrons must enter a new shell with higher energy, closed-shell electron configurations are markedly more stable, leading to the relative inertness of the noble gases. Since protons and neutrons are also known to arrange themselves in closed nuclear shells, the same effect happens at nucleon shell closures, which happen at specific nucleon numbers often dubbed ""magic numbers"". The known magic numbers are 2, 8, 20, 28, 50, and 82 for protons and neutrons, and additionally 126 for neutrons. Nucleons with magic proton and neutron numbers,"
"or neon are known. The noble gases—including helium—can form stable molecular ions in the gas phase. The simplest is the helium hydride molecular ion, HeH, discovered in 1925. Because it is composed of the two most abundant elements in the universe, hydrogen and helium, it is believed to occur naturally in the interstellar medium, although it has not been detected yet. In addition to these ions, there are many known neutral excimers of the noble gases. These are compounds such as ArF and KrF that are stable only when in an excited electronic state; some of them find application in"
"a noble gas until 1904 when its characteristics were found to be similar to those of other noble gases. Rayleigh and Ramsay received the 1904 Nobel Prizes in Physics and in Chemistry, respectively, for their discovery of the noble gases; in the words of J. E. Cederblom, then president of the Royal Swedish Academy of Sciences, ""the discovery of an entirely new group of elements, of which no single representative had been known with any certainty, is something utterly unique in the history of chemistry, being intrinsically an advance in science of peculiar significance"". The discovery of the noble gases"
"since all isotopes are radiogenic nuclides from radioactive decay. (It is not known if any synthetic elements with atomic number above 108 are gases.) The elements which are stable two atom homonuclear molecules at standard temperature and pressure (STP), are hydrogen (H), nitrogen (N) and oxygen (O), plus the halogens fluorine (F) and chlorine (Cl). The noble gases are all monatomic. In the industrial gases industry the term ""elemental gases"" (or sometimes less accurately ""molecular gases"") is used to distinguish these gases from molecules that are also chemical compounds. These elements are all nonmetals. Radon is chemically stable, but it"
"periods of the periodic table, the noble gases are exactly the members of group 18. Noble gases are typically highly unreactive except when under particular extreme conditions. The inertness of noble gases makes them very suitable in applications where reactions are not wanted. For example, argon is used in incandescent lamps to prevent the hot tungsten filament from oxidizing; also, helium is used in breathing gas by deep-sea divers to prevent oxygen, nitrogen and carbon dioxide (hypercapnia) toxicity. The properties of the noble gases can be well explained by modern theories of atomic structure: their outer shell of valence electrons"
"is considered to be ""full"", giving them little tendency to participate in chemical reactions, and it has been possible to prepare only a few hundred noble gas compounds. The melting and boiling points for a given noble gas are close together, differing by less than ; that is, they are liquids over only a small temperature range. Neon, argon, krypton, and xenon are obtained from air in an air separation unit using the methods of liquefaction of gases and fractional distillation. Helium is sourced from natural gas fields which have high concentrations of helium in the natural gas, using cryogenic"
"put in a gas cylinder (except perhaps if it is used as a fuel) Propane would be considered an industrial gas when used as a refrigerant, but not when used as a refrigerant in LNG production, even though this is an overlapping technology. The known chemical elements which are, or can be obtained from natural resources and which are gaseous are hydrogen, nitrogen, oxygen, fluorine, chlorine, plus the noble gases; and are collectively referred to by chemists as the ""elemental gases"". These elements are all primordial apart from the noble gas radon which is a trace radioisotope which occurs naturally"
"noble gases show extremely low chemical reactivity; consequently, only a few hundred noble gas compounds have been formed. Neutral compounds in which helium and neon are involved in chemical bonds have not been formed (although there is some theoretical evidence for a few helium compounds), while xenon, krypton, and argon have shown only minor reactivity. The reactivity follows the order Ne < He < Ar < Kr < Xe < Rn. In 1933, Linus Pauling predicted that the heavier noble gases could form compounds with fluorine and oxygen. He predicted the existence of krypton hexafluoride () and xenon hexafluoride (),"
"Argon Argon is a chemical element with symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in the Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 23 times as abundant as carbon dioxide (400 ppmv), and more than 500 times as abundant as neon (18 ppmv). Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust. Nearly all of the argon in"
"processes. There are also breaks in the abundance graph where the six noble gases would be, since they are not chemically bound in the Earth's crust, and they are only generated by decay chains from radioactive elements in the crust, and are therefore extremely rare there. The eight naturally occurring very rare, highly radioactive elements (polonium, astatine, francium, radium, actinium, protactinium, neptunium, and plutonium) are not included, since any of these elements that were present at the formation of the Earth have decayed away eons ago, and their quantity today is negligible and is only produced from the radioactive decay"
"see list of states of matter. The only chemical elements that are stable diatomic homonuclear molecules at STP are hydrogen (H), nitrogen (N), oxygen (O), and two halogens: fluorine (F) and chlorine (Cl). When grouped together with the monatomic noble gases – helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn) – these gases are called ""elemental gases"". The word ""gas"" was first used by the early 17th-century Flemish chemist Jan Baptist van Helmont. He identified carbon dioxide, the first known gas other than air. Van Helmont's word appears to have been simply a phonetic transcription"
"they are less strongly attracted to the positively charged nucleus. This results in an ionization energy low enough to form stable compounds with the most electronegative elements, fluorine and oxygen, and even with less electronegative elements such as nitrogen and carbon under certain circumstances. When the family of noble gases was first identified at the end of the nineteenth century, none of them was observed to form any compounds and it was initially believed that they were all ""inert gases"" (as they were then known) which could not form compounds. With the development of atomic theory in the early twentieth"
"so completely exploited that their value as minerals has almost completely disappeared. The atmophile elements are: H, C, N and the noble gases. Atmophile elements (also called ""volatile elements"") are defined as those that remain mostly on or above the surface because they are, or occur in, liquids and/or gases at temperatures and pressures found on the surface. The noble gases do not form stable compounds and occur as monatomic gases, while nitrogen, although it does not have a stable configuration for its individual atoms, forms a diatomic molecule so strong that all oxides of nitrogen are thermodynamically unstable with"
"noble-gas molecule detected in outer space. Solid argon hydride (Ar(H)) has the same crystal structure as the MgZn Laves phase. It forms at pressures between 4.3 and 220 GPa, though Raman measurements suggest that the H molecules in Ar(H) dissociate above 175 GPa. Argon is produced industrially by the fractional distillation of liquid air in a cryogenic air separation unit; a process that separates liquid nitrogen, which boils at 77.3 K, from argon, which boils at 87.3 K, and liquid oxygen, which boils at 90.2 K. About 700,000 tonnes of argon are produced worldwide every year. Ar, the most abundant"
"suggesting a solar-neon reservoir in the Earth. Neon is the second-lightest noble gas, after helium. It glows reddish-orange in a vacuum discharge tube. Also, neon has the narrowest liquid range of any element: from 24.55 K to 27.05 K (−248.45 °C to −245.95 °C, or −415.21 °F to −410.71 °F). It has over 40 times the refrigerating capacity (per unit volume) of liquid helium and three times that of liquid hydrogen. In most applications it is a less expensive refrigerant than helium. Neon plasma has the most intense light discharge at normal voltages and currents of all the noble gases."
"gas. Neon has three stable isotopes: Ne (90.48%), Ne (0.27%) and Ne (9.25%). Ne and Ne are partly primordial and partly nucleogenic (i.e. made by nuclear reactions of other nuclides with neutrons or other particles in the environment) and their variations in natural abundance are well understood. In contrast, Ne (the chief primordial isotope made in stellar nucleosynthesis) is not known to be nucleogenic or radiogenic. The causes of the variation of Ne in the Earth have thus been hotly debated. The principal nuclear reactions generating nucleogenic neon isotopes start from Mg and Mg, which produce Ne and Ne respectively,"
"of Ar, Kr, and Xe. (For instance, radioactive isotopes of krypton and xenon are difficult to store and dispose, and compounds of these elements may be more easily handled than the gaseous forms.) In addition, clathrates of radioisotopes may provide suitable formulations for experiments requiring sources of particular types of radiation; hence. Kr clathrate provides a safe source of beta particles, while Xe clathrate provides a useful source of gamma rays. Noble gas compound Noble gas compounds are chemical compounds that include an element from the noble gases, group 18 of the periodic table. Although the noble gases are generally"
"After the risks caused by the flammability of hydrogen became apparent, it was replaced with helium in blimps and balloons. ""Noble gas"" is translated from the German noun , first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity. The name makes an analogy to the term ""noble metals"", which also have low reactivity. The noble gases have also been referred to as ""inert gases"", but this label is deprecated as many noble gas compounds are now known. ""Rare gases"" is another term that was used, but this is also inaccurate because argon forms a"
"1886 many researchers tried to obtain it. Fluorine was eventually isolated in 1886 by Moissan. Germanium: In mid-1885, at a mine near Freiberg, Saxony, a new mineral was discovered and named ""argyrodite"" because of its silver content. The chemist Clemens Winkler analyzed this new mineral, which proved to be a combination of silver, sulfur, and a new element, germanium, which he was able to isolate in 1886. Argon: Lord Rayleigh and Ramsay discovered argon in 1894 by comparing the molecular weights of nitrogen prepared by liquefaction from air, and nitrogen prepared by chemical means. It was the first noble gas"
"these interactions became tractable because the noble gases are monatomic and the atoms spherical, which means that the interaction between the atoms is independent of direction, or isotropic. The noble gases are colorless, odorless, tasteless, and nonflammable under standard conditions. They were once labeled ""group 0"" in the periodic table because it was believed they had a valence of zero, meaning their atoms cannot combine with those of other elements to form compounds. However, it was later discovered some do indeed form compounds, causing this label to fall into disuse. Like other groups, the members of this family show patterns"
"as in other metallurgical processes and in the production of silicon for the semiconductor industry. Noble gases are commonly used in lighting because of their lack of chemical reactivity. Argon, mixed with nitrogen, is used as a filler gas for incandescent light bulbs. Krypton is used in high-performance light bulbs, which have higher color temperatures and greater efficiency, because it reduces the rate of evaporation of the filament more than argon; halogen lamps, in particular, use krypton mixed with small amounts of compounds of iodine or bromine. The noble gases glow in distinctive colors when used inside gas-discharge lamps, such"
"Neon Neon is a chemical element with symbol Ne and atomic number 10. It is a noble gas. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. It was discovered (along with krypton and xenon) in 1898 as one of the three residual rare inert elements remaining in dry air, after nitrogen, oxygen, argon and carbon dioxide were removed. Neon was the second of these three rare gases to be discovered and was immediately recognized as a new element from its bright red emission spectrum. The name neon is derived from"
"to be retained. Neon, argon, krypton, and xenon also form clathrate hydrates, where the noble gas is trapped in ice. Noble gases can form endohedral fullerene compounds, in which the noble gas atom is trapped inside a fullerene molecule. In 1993, it was discovered that when , a spherical molecule consisting of 60 carbon atoms, is exposed to noble gases at high pressure, complexes such as can be formed (the ""@"" notation indicates He is contained inside but not covalently bound to it). As of 2008, endohedral complexes with helium, neon, argon, krypton, and xenon have been obtained. These compounds"
"air. Replacement of the air with a noble gas considerably increases the light output; with molecular gases, the energy is consumed partially by dissociation and other processes, while noble gases are monatomic and can only undergo ionization; the ionized gas then produces the light. The low specific heat capacity of noble gases allows heating to higher temperatures, yielding brighter emission. Flashtubes are filled with noble gases for the same reason. Typical argon flash devices consist of an argon-filled cardboard or plastic tube with a transparent window on one end and an explosive charge on the other end. Many explosives can"
"Noble gas configuration Noble gas configuration is the electron configuration of noble gases. The basis of all chemical reactions is the tendency of chemical elements to acquire stability. For some main group elements, chemical bond formation often results in a complete electronic configuration resembling a noble gas. W. Kossel and Gilbert N. Lewis saw that noble gases did not have the tendency of taking part in chemical reactions under ordinary conditions. On the basis of this observation they concluded that atoms of noble gases are stable and on the basis of this conclusion they proposed a theory of valency known"
"applied at a temperature of to convert it to a solid. The noble gases up to xenon have multiple stable isotopes. Radon has no stable isotopes; its longest-lived isotope, Rn, has a half-life of 3.8 days and decays to form helium and polonium, which ultimately decays to lead. Melting and boiling points generally increase going down the group. The noble gas atoms, like atoms in most groups, increase steadily in atomic radius from one period to the next due to the increasing number of electrons. The size of the atom is related to several properties. For example, the ionization potential"
"For gasses, the number of nines is usually written after the letter N, rather than before it. An N2.0 gas is 99% pure, and 1% (by volume) impurities. An N6.0 gas is 99.9999% (six nines) pure, with 1 part per million (1 ppm) impurities. Intermediate values are formed using the common logarithm. For example, a gas which is 99.97% pure would be described as N3.5, since log(0.03%) = −3.523. Nines are used in a similar manner to describe computer system availability. Nine (purity) Nines are an informal, yet common method of grading the purity of materials. very fine precious metals"