The sum of lone pairs present on the central atom of the...

In ${IF}_{5}$, the central atom is iodine, which has $7$ valence electrons. Iodine in this molecule has $5$ bonding pairs and $1$ lone pair. Therefore, the number of lone pairs on the central atom of ${IF}_{5}$ is $1$.

In ${IF}_{7}$, the central atom is also iodine, which has $7$ valence electrons. Iodine in this molecule has $7$ bond pairs and $0$ lone pairs. Therefore, the number of lone pairs on the central atom of ${IF}_{7}$ is $0$.

Therefore, the sum of the number of lone pairs in the central atom of ${IF}_{5}$ and ${IF}_{7}$ is $1 + 0 = 1 .$.