Question

Why are helium and neon gases called `"inert gases"`?

Answer 1

Because no compounds of helium and neon are known.

Explanation:

The answer is simply because neither helium nor neon are known to bind to other elements (`He_2^+` is known, but it's not something you could put in a bottle). Therefore, they cannot share, accept, or donate electrons. The valence electrons of Group VIII, the Noble Gases, have a very stable closed shell configuration, which resists chemical change. Hence they are considered zerovalent.