Question

Nitrogen forms stable $N_2$ molecule but phosphorus is converted to $P_4$ from $P_2$ because:

• A. p$\pi$-p$\pi$ bonding is strong in phosphorus
• B. p$\pi$-p$\pi$ bonding is weak in phosphorus
• C. triple bond is present in phosphorus
• D. single $P-P$ bond is weaker than $N-N$ bond

Answer 1

The correct option is B p$\pi$-p$\pi$ bonding is weak in phosphorus

$P$ has empty $d$ orbital, that can be filled by an additional electron. And since its size is bigger it is least likely to handle triple bond, as size increases $\pi$ overlapping decreases.