What is a noble gas?

Answer 1

Any of the elements in Group O of the Periodic Table, including helium, neon, argon, krypton, xenon, and radon, which are monatomic and with limited exceptions chemically inert. Also called inert gas.

Answer 2

The noble gases are in group 18 of the modern periodic table. The gases are monatomic- that is they contain single single atoms not molecules. They are all relatively chemically inert particularly helium and neon which form no compounds. They are colorless and odourless. There are six noble gases helium, neon, argon, krypton, xenon and radon.