noble gas

The noble gases are the elements in group 18 (also sometimes Group 0 IUPAC Style, or Group 8) of the periodic table. It is also called helium family or neon family. Chemically, they are very stable due to having the maximum number of valence electrons their outer shell can hold. A thorough explanation requires an understanding of electronic configuration, with references to quantum mechanics. Noble gases rarely react with other elements since they are already stable. Under normal conditions, they occur as odorless, colorless, monatomic gases. Each of them has its melting and boiling point close together, so that only a small temperature range exists for each noble gas in which it is a liquid. Noble gases have numerous important applications in lighting, welding and space technology.
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Noun
1. any of the chemically inert gaseous elements of the helium group in the periodic table
(synonym) inert gas, argonon
(hypernym) chemical element, element
(hyponym) argon, Ar, atomic number 18

A gaseous chemical element that does not readily enter into chemical combination with other elements. An inert gas. Examples are helium, argon, krypton, xenon, and radon.