Noble gas refers to any element of the group of six elements in group 8 of the periodic table. They are argon, helium, krypton, neon, radon, and xenon. Unlike most elements, the nobel gases are monoatomic. The atoms have stable configurations of electrons. Therefore under normal conditions they do not form compounds with other elements.

They were generally called inert gases until about 1962 when xenon tetrafluoride, XeF4, was produced in the laboratory. This was the first report of a stable compound of a nobel gas with another single element.