Find the valence electrons on the central atom iodine

Iodine belongs to group 17, so it has $7$ valence electrons.

Lone pairs in $\mathrm{IF_5}$

• Central atom: $\mathrm{I}$
• It forms $5$ sigma bonds with $5$ fluorine atoms.
• Out of iodine’s $7$ valence electrons, $5$ are used in bonding.
• Remaining electrons on iodine: $7 - 5 = 2 \text{ electrons}$
• These $2$ electrons form: $1 \text{ lone pair}$

Lone pairs in $\mathrm{IF_7}$

• Central atom: $\mathrm{I}$
• It forms $7$ sigma bonds with $7$ fluorine atoms.
• All $7$ valence electrons are used in bonding.
• Remaining electrons on iodine: $7 - 7 = 0$
• So lone pairs on iodine in $\mathrm{IF_7}$ are: $0$

Total lone pairs on the central atom

$1 + 0 = 1$

Final Answer

The required sum is: $\boxed{1}$