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 the octet rule.

Answer 1

The correct option is B

Because hydrogen can accommodate a maximum of 2 electrons in its first shell.

Hydrogen can accommodate a maximum of 2 electrons in the first shell (k-shell = $2n^2$ = 2 (n=1)).
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. He and becomes stable like helium.