Question

Single $N-N$ bond is weaker than the single $P-P$ bond. This is because of:

• A. larger $N-N$ bond length in comparison to $P-P$ bond length
• B. high interelectronic repulsion of the non-bonding electrons, owing to the small $N-N$ bond length in comparison to that in $P-P$ single bond
• C. higher electronegativity of $N$ in comparison to $P$
• D. smaller atomic size of $N$ as compared to that of $P$

Answer 1

Answer: (B), (D)

The correct options are
B high interelectronic repulsion of the non-bonding electrons, owing to the small $N-N$ bond length in comparison to that in $P-P$ single bond
D smaller atomic size of $N$ as compared to that of $P$

$N-N$ single bond is weaker than $P-P$ bond due to smaller size of $N$ as compared to $P$. Smaller size of $N$ leads to smaller $N-N$ bond length. As a result, the lone pair of electrons on the both the $N$ atoms repel each other leading to unstability or weakening of $N-N$ bond. Because of larger size of $P$ atom, $P-P$ bond length is more and lone pair-lone pair repulsion between $P$ atoms is less which makes the $P-P$ bond stronger than $N-N$ bond.