In IF5, 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 IF5 is 1.
In IF7, 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 IF7 is 0.
Therefore, the sum of the number of lone pairs in the central atom of IF5 and IF7 is 1+0=1..
