Statement I : Bond angle in NH₃ is around 107^o where as in other hydrides it is around 90^o

Statement II : Hybrid orbitals are involved in bonding  in NH₃ where as pure p-orbitals in other hydrides

$\cos \theta ==\frac{\mathrm{s}}{\mathrm{s}-1}=\frac{\mathrm{p}-1}{\mathrm{p}}; \mathrm{\theta }$ in NH₃ is 107⁰.  The calculated p- character  is around 75%.

Thus the hybridisation in NH₃ is sp³

$\mathrm{\theta }$in PH₃ is 93.6⁰ , the calculated p- character  is around 97%.

Thus we assume that pure p-orbitals participate in bonding in PH_3,  AsH₃ & SbH₃.