Question

The property of hydrogen which distinguishes it from alkali metals is

• A. Its electropositive character
• B. Its affinity for non metal
• C. Its reducing character
• D. its non-metallic character

Answer 1

The correct option is D its non-metallic character

Hydrogen is a non-metal while all other members of group 1 (alkali metals) are metals.

THEORY
Dissimilarities between H and alkali metals:
1. Ionisation energy of H is very high. $H^{+}$ has a smaller size compared to alkali metal ions.
2. Difficult to assign any definite position to hydrogen in the periodic table