The noble gases (historically the inert gases, sometimes referred to as aerogens[1]) are the naturally occurring members of group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Under standard conditions, these elements are odorless, colorless, monatomic gases with very low chemical reactivity and cryogenic boiling points.
The noble gases' inertness, or tendency not to react with other chemical substances, results from their electron configuration: their outer shell of valence electrons is "full", giving them little tendency to participate in chemical reactions. Only a few hundred noble gas compounds are known to exist. For the same reason[clarification needed], noble gas atoms are small, and the only intermolecular force between them is the very weak London dispersion force, so their boiling points are all cryogenic, below 165 K (−108 °C; −163 °F).[2]
The inertness of noble gases makes them useful whenever chemical reactions are unwanted. For example, argon is used as a shielding gas in welding and as a filler gas in incandescent light bulbs. After the risks caused by the flammability of hydrogen became apparent in the Hindenburg disaster, hydrogen was replaced with helium in blimps and balloons. Helium and neon are also used as refrigerants due to their low boiling points. Industrial quantities of the noble gases, except for radon, are obtained by separating them from air using the methods of liquefaction of gases and fractional distillation. Helium is also a byproduct of the mining of natural gas. Radon is usually isolated from the radioactive decay of dissolved radium, thorium, or uranium compounds.
The seventh member of group 18 is oganesson (Og), an unstable synthetic element whose chemistry is still uncertain because only five very short-lived atoms (t1/2 = 0.69 ms) have ever been synthesized (as of 2020[update][3]). IUPAC uses the term "noble gas" interchangeably with "group 18" and thus includes oganesson;[4] however, due to relativistic effects, oganesson is predicted to be a solid under standard conditions and reactive enough not to qualify functionally as "noble".[3] In the rest of this article, the term "noble gas" should be understood not to include oganesson unless it is specifically mentioned.
^Bauzá, Antonio; Frontera, Antonio (2015). "Aerogen Bonding Interaction: A New Supramolecular Force?". Angewandte Chemie International Edition. 54 (25): 7340–3. doi:10.1002/anie.201502571. PMID 25950423.
^"Xenon | Definition, Properties, Atomic Mass, Compounds, & Facts". Britannica. 28 November 2023. Retrieved 12 January 2024.
^ abSmits, Odile R.; Mewes, Jan-Michael; Jerabek, Paul; Schwerdtfeger, Peter (2020). "Oganesson: A Noble Gas Element That Is Neither Noble Nor a Gas" (PDF). Angewandte Chemie International Edition. 59 (52): 23636–23640. doi:10.1002/anie.202011976. PMC 7814676. Archived from the original on 16 December 2023. Retrieved 23 October 2023.
^Koppenol, W. (2016). "How to name new chemical elements" (PDF). Pure and Applied Chemistry. DeGruyter. doi:10.1515/pac-2015-0802. hdl:10045/55935. S2CID 102245448. Archived (PDF) from the original on 18 December 2023.
The noblegases (historically the inert gases, sometimes referred to as aerogens) are the naturally occurring members of group 18 of the periodic table:...
configuration can be visualized as the core electrons, equivalent to the noblegas of the preceding period, and the valence electrons: each element in a...
compounds. The noblegases often do not react with many substances and were historically referred to as the inert gases. Inert gases are used generally...
together with the homonuclear diatomic gases such as nitrogen (N2), the noblegases are called "elemental gases" to distinguish them from molecules that...
liquid, and plasma. A pure gas may be made up of individual atoms (e.g. a noblegas like neon), elemental molecules made from one type of atom (e.g. oxygen)...
the leftmost column (the alkali metals) to the rightmost column (the noblegases). The f-block groups are ignored in this numbering. Groups can also be...
different meanings in different fields of study and application (see Noblegas). Prior to Mendeleev's publication in 1869 of the first (eventually) widely...
they are called inert gases. The noblegases (helium, neon, argon, krypton, xenon and radon) were previously known as 'inert gases' because of their perceived...
increases. It takes a noblegas atom in an excited electronic state to form an excimer molecule such as a noblegas dimer or noblegas halide. Sufficiently...
In contrast, nonmetals share only the electrons required to achieve a noblegas electron configuration. For example, nitrogen forms diatomic molecules...
web drama Noble savage, a literary stock character Noble Warriors, a fantasy series, trilogy Noblegas (data page) NoblegasNoble metal Noble (English...
structure of noblegas molecules makes them amenable to accurate theoretical treatment. For this reason, measured viscosities of the noblegases serve as...
has symbol Xe and atomic number 54. It is a dense, colorless, odorless noblegas found in Earth's atmosphere in trace amounts. Although generally unreactive...
colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noblegas group in the periodic table. Its boiling point is the lowest...
for the last previous noblegas in the periodic table, placed in square brackets. For phosphorus, the last previous noblegas is neon, so the configuration...
(called periodicity). For example, all elements in group (column) 18 are noblegases that are largely—though not completely—unreactive. The history of the...
The International NobleGas Experiment (INGE) was formed in 1999 as an informal expert's group of developers of radioactive xenon measurement systems...
is a noblegas. Most hexafluorides are molecular compounds with low melting and boiling points. Four hexafluorides (S, Se, Te, and W) are gases at room...
The noblegases are all monatomic. In the industrial gases industry the term "elemental gases" (or sometimes less accurately "molecular gases") is used...
An atom with a closed shell of valence electrons (corresponding to a noblegas configuration) tends to be chemically inert. Atoms with one or two valence...
other scientists including Julius Lothar Meyer. The inert gases, later called the noblegases were discovered by William Ramsay in collaboration with Lord...
atomic number 10. It is the second noblegas in the periodic table. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with approximately...
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