Question

Which one of the following doesn’t come under zero group?

• A. He
• B. K
• C. Ne
• D. Ar

Answer 1

The correct option is B

K

Explanation for Correct option:

B) Potassium(K) is an alkali metal that belongs to IA group and has 1 valence electron in its outermost shell.

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^1$- electronic configuration

Hence, it does not belong to zero group.

Explanation for incorrect options:

A) Helium(He) is an inert gas with completely filled valence shell and shows inertness towards other elements.

$1s^2$ - electronic configuration

C)Neon(Ne) is an inert gas with completely filled valence shell and shows inertness towards other elements.

$1s^{2}2s^{2}2p^6$- electronic configuration

D) Argon(Ar) is an inert gas with completely filled valence shell and shows inertness towards other elements.

$1s^{2}2s^{2}2p^{6}3s^{2}3p^6$- electronic configuration

Since, He, Ne, Ar have completely filled valence shell and shows zero valency, they belong to zero group.

Hence,A) is the correct option- K does not belong to zero group.