Question

In nitrogen family, the $H -M- H$ bond angle in the hydrides gradually becomes closer to $90^{\circ}$ on going form $N$ to $Sb$. This shows that gradually

• A. the basic strength of the hydrides increases
• B. almost pure $p$ -orbitals are used for $M- H$ bonds
• C. the bond energies of $M- H$ bonds increase
• D. the bond pairs of electrons become nearer to the central atom.

Answer 1

Answer: (B)

On moving down the group, electronegativity decreases, consequently bond pair shifts more and more away from the central atom. Hence, $H -M- H$ bond angle decreases and becomes closer to $90^{\circ}$ in $SbH _{3}$ which reveals that almost pure $p$ -orbitals are used for $M- H$ bonding.