Question

Why does nitrogen show catenation properties less than phosphorus?

Answer 1

$N-N$ single bond is weak as nitrogen has small size and lone pairs on two $N$ atoms repel each other. Phosphorous has larger atomic size and the lone pairs on $P$ repel to smaller extent. Thus, the strength of $P-P$ bond is greater than the strength of $N-N$ bond. High bond enthalpy of $P-P$ bond results in tendency for catenation.