The correct order of single bond energies is :

Due to N's lesser size compared to P, NN single bonds are weaker than PP bonds. NN bond length is influenced by the magnitude of N.

The correct order of single bond energies are:

$$\begin{gathered} \mathrm{P}-\mathrm{P}>\mathrm{N}-\mathrm{N}; \\ \mathrm{O}-\mathrm{O}<\mathrm{S}-\mathrm{S}; \\ \mathrm{C}-\mathrm{C}>\mathrm{Si}-\mathrm{Si} \end{gathered}$$