Question

Why does nitrogen show catenation properties less than phosphorus?

Answer 1

1. Catenation is much more common in phosphorous compounds than in nitrogen compounds.
2. This is because of the relative weakness of the N-N single bond as compared to the P-P (201.6 kJ mol⁻¹) single bond. 
3. Since the nitrogen atom is smaller, there is greater repulsion of electron density of two nitrogen atoms, thereby weakening the N-N (163.8 kJ mol⁻¹) single bond.