AllChemicals — The Online Chemical Glossary | https://allchemicals.info/chemical/605-noble-gas
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Quick Reference
Also Known As
Inert gases (historical), rare gases, Group 18 elements, Group VIII gases
What is Noble Gas?
Elements in Group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Noble gases have completely filled valence shells (except helium, with 2 electrons), making them very unreactive. Used in lighting, welding, and as inert atmospheres.
Properties & Characteristics
Noble gases are the Group 18 elements: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). They have completely filled valence shells (ns²np⁶, except He: 1s²), giving them very high ionisation energies and very low electron affinities. For decades they were called "inert gases" because no compounds were known, but since 1962 (Bartlett's XePtF₆), stable noble gas compounds of Xe and Kr have been prepared.
Uses & Applications
Noble gases are used as: inert atmospheres for reactive chemistry and metallurgy (Ar, N₂), cryogenic coolants (He at 4.2 K for superconducting magnets, liquid He for MRI), lighting (Ne in neon signs, Ar/Kr in incandescent bulbs, Xe in high-intensity lamps), medical anesthesia (Xe is an anaesthetic), and leak detection (He tracer gas in vacuum systems).
Safety Information
Noble gases are asphyxiants — they displace oxygen in confined spaces, causing death from hypoxia without warning (no odour, no irritation). Cryogenic noble gas liquids (liquid He, liquid Ar) cause cryogenic burns and can cause oxygen-enriched atmospheres on evaporation. Radon (Rn-222) is a radioactive noble gas that is a leading cause of lung cancer after smoking.
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
SynonymsInert gases (historical), rare gases, Group 18 elements, Group VIII gases
Frequently Asked Questions
Elements in Group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Noble gases have completely filled valence shells (except helium, with 2 electrons), making them very unreactive. Used in lighting, welding, and as inert atmospheres.
Noble gases are used as: inert atmospheres for reactive chemistry and metallurgy (Ar, N₂), cryogenic coolants (He at 4.2 K for superconducting magnets, liquid He for MRI), lighting (Ne in neon signs, Ar/Kr in incandescent bulbs, Xe in high-intensity lamps), medical anesthesia (Xe is an anaesthetic),…
Noble gases are asphyxiants — they displace oxygen in confined spaces, causing death from hypoxia without warning (no odour, no irritation). Cryogenic noble gas liquids (liquid He, liquid Ar) cause cryogenic burns and can cause oxygen-enriched atmospheres on evaporation. Radon (Rn-222) is a radioact…
Editorial standards: Chemical data is sourced from peer-reviewed literature,
CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA,
and IAEA. For educational purposes only — always consult official SDS documentation and qualified
professionals before handling chemicals.
