Question

Which of the noble gases are molecules or compounds?

Answer 1

The noble gases do form chemical compounds, even though they have filled electron valence shells.

Helium, neon, argon, krypton, xenon, radon have completed valence electron shells, so they are highly stable. However, the filled inner electron shells tend to provide a sort of electrical shielding, making it possible to ionize the outer electrons. Under ordinary conditions, noble gases are inert and don't form compounds, but when ionized or under pressure, they will sometimes working into the matrix of another molecule or combine with highly reactive ions. Reaction with halogens is most favorable, where the noble gas loses an electron and acts as a positively charged ion to form a compound.