Phosphorus shows greater tendency for catenation than nitrogen. Explain.

Explanation

Due to smaller size, the unshared electron pairs on the two N-atoms repel the bond pair of the N - N bond. In contrast, the lone-pairs of electrons on the two P-atoms do not repel the bond-pair of the P- P bond to the same extent due to the larger size of the P-atom. As a result, the N - N single bond is weaker `(159kJcdotmol^(-1))` than the P-P single bond `(213 kJcdotmol^(-1))`. Consequently nitrogen exhibits little tendency or catenation or phosphorus shows greater tendency for catenation than nitrogen.