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

Answer: (B)

$p\pi -p\pi$ bonding is weak in phosphorus

Answer 2

$p\pi$ - $p\pi$ bonding in nitrogen is strong hence it can form triple bond with another $N$. Single $N - N$ bond is weaker than $P - P$ bond due to high interionic repulsion of non-bonding electrons. Hence, $N = N$ is stable and $P_2$ is not.