Phosphorous can form `PCl_(5)` molecule in the excited state of phosphorous atom. But the formation of `PH_(5)` is not possible in the same state. Account for this.

Explanation

(i) valence electronic configuration of hydrogen and chlorine
(ii) type of hybridisation in `PCl_(5)`
(iii) comparison of electronegativities between hydrogen and chlorine
(iv) the difference between the energies of overlapping orbitals