Valency is a combining capacity of an element. As there are no free electrons in the valence shell and the elements are already in a stable state, the noble gases’ valency is zero.
Why is the valency of inert gases zero?
The atoms of noble gases already have complete outer shells, so they do not lose, gain, or share electrons. This is why the noble gases are inert and do not take part in chemical reactions. Inert gases have very high ionisation enthalpy because they have a stable electronic configuration. Therefore, they do not tend to lose electrons. Thus, the valency of inert gases is zero.
- The six naturally occurring noble gases are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radioactive radon (Rn).
- Lewis postulated that inert gas atoms are chemically inert because they hold 8 valence electrons.
- The valence electron pattern in these atoms is called an inert gas electron configuration.