The bond angle in $\mathrm{NF}_{3}\left(102.3^{\circ}ight)$ is smaller than $\mathrm{NH}_{3}\left(107…
The bond angle in $\mathrm{NF}_{3}\left(102.3^{\circ}ight)$ is smaller than $\mathrm{NH}_{3}\left(107.2^{\circ}ight) .$ This is because of
large size of F compared to H
large size of N compared to F
opposite polarity of $\mathrm{N}$ in the two molecules
small size of $\mathrm{H}$ compared to $\mathrm{N}$
Solution
In $\mathrm{NF}_{3}$, $\mathrm{N}$ is less electronegative as compared to F but in $\mathrm{NH}_{3}$, it is more electronegative than $\mathrm{H}$. And in case of same central atom. as the electronegativity of other atoms increases, bond angle decreases, Thus, bond angle in $\mathrm{NF}_{3}$ is smaller than that in $\mathrm{NH}_{3}$ because of the difference in the polarity of $\mathrm{N}$ in these molecules.
