The H-N-H angle vlaue is higher than H-P-H, H-AsH and H-SbH angles. Why?
The central atom E (Where, E =N,P, As, Sb, Bi) in all given hydrides is \(sp-3) hybridized. However, its electronegativity decreases and atomic size increases on moving down the group. Therefore, there is a gradual moving down the group. Therefore, there is a gradual decrease in the force of repulsion between the shared electron pairs around the central atom. Thus, bond angle decreases as we move down the group.
MoleculeNH3PH3AsH3SbH3BiH3Bond angle107.8∘93.6∘91.8∘91.3∘90∘