Question

PH3 has the same geometry as NH3, however, the bond angle in PH3 is less than that in NH3. Provide an explanation for this observation. 

Answer 1

The bond angle in NH3​ is larger than, in PH3​ because the P−H bonds are longer and the lower electronegativity of P permits electron-density to be displaced towards hydrogen to a greater extent than in the case of NH3.