Question

Why is catenation property of phosphorus greater than nitrogen?

Answer 1

Catenation is the bonding of atoms of the same element into series called a chain. Thus, higher the stability of single bond between the same atom more will be its affinity to undergo catenation.
The single N-N bond in nitrogen is weaker than the P-P bond in phosphorus because of high inter-electronic repulsion of the non-bonding electrons, owing to the small bond length. As a result, the catenation tendency is weaker in nitrogen.
N-N single bond is much weaker than P-P due to the presence more repulsion of lone pairs on nitrogen atom as compared to the P-P single bond lone pairs. As nitrogen atom is smaller, there is greater repulsion of electron density of two nitrogen atoms, which in turn weakens the N-N single bond and decreases the tendency of nitrogen to show catenation.