Question

All elements combine to obey octet rule except hydrogen. Why?

• A. Because hydrogen is in gaseous state.
• B. Because hydrogen can accommodate a maximum of 2 electrons in its first shell.
• C. Because hydrogen is metal
• D. No, the question is wrong. Hydrogen obeys octet rule

Answer 1

The correct option is B Because hydrogen can accommodate a maximum of 2 electrons in its first shell.

Because hydrogen can accommodate a maximum of 2 electrons in the first shell (K-shell $\to$ $2n^2=2$ as (n=1 for K-shell)), thus it does not obey the octet rule. But by obtaining 2 electrons in its valence shell, it attains the nearest noble gas configuration i.e. helium and becomes stable like helium.