Why is the single N – N is weaker than the single P – P bond?

P – Psingle bond is stronger than N – Nbond due to larger size of P as compared to N. Smaller size of Nitrogen leads to the formation of smaller N – Nbond length. As a result, the lone pair of electrons on both the N atoms repel each other leading to un-stability or weakening of N – Nbond. On the other hand, due to the larger size of P atom,P – Pbond length is more and lone pair-lone pair repulsion between P atoms is less.Thus, the single P – Pbond is stronger than single N – N bond.