NEET Chemistry The p-Block Elements (XII) Questions Solved

(i) Due to presence of d-orbitals in P, it can form $p\pi -d\pi$ bonds and can extend its covalency beyond 4 while N cannot do so due to absence of d-orbitals.

(ii) According to Fajan's rule, highly charged $P{b}^{4+}$ can polarise the anion i.e., $C{l}^{-}$ more effectively than $P{b}^{2+}$ and hence $PbC{l}_4$ becomes more covalent than $PbC{l}_2.$

(iii) Due to presence of triple bonds between 2N atoms, their bond length decreases and hence bond dissociation energy increases which makes $N_2$ lesser reactive. While in phosphorus due to presence of single bond, more bond length, bond dissociation energy is low, hence very reactive.