Question

The Sum of number of lone pairs in central atom in IF₅ and IF₇ is:

Answer 1

In IF₅ (iodine pentafluoride), the central atom is iodine (I).
Iodine has 7 valence electrons (group 7 or 17), and each fluorine (F) atom has 7 valence electrons. Therefore, the total number of valence electrons in IF₅ is:
1(I) x 7 valence electrons + 5(F) x 7 valence electrons = 42 valence electrons
To determine the number of lone pairs on the central atom, we need to subtract the number of electrons involved in bonding from the total number of valence electrons.
In IF₅, each fluorine atom contributes 1 electron to form a single bond with the iodine atom. Therefore, there are 5 bonding pairs (I-F) in the molecule, accounting for a total of 10 electrons.
The remaining 32 valence electrons are used to complete the octet of each fluorine atom, leaving 2 electrons on iodine. Since each lone pair has 2 electrons, there is 1 lone pair on the central atom in IF₅.
In IF₇ (iodine heptafluoride), the central atom is also iodine (I).
Iodine has 7 valence electrons, and each fluorine atom has 7 valence electrons. Therefore, the total number of valence electrons in IF₇ is:
1(I) x 7 valence electrons + 7(F) x 7 valence electrons = 56 valence electrons
In IF₇, each fluorine atom contributes 1 electron to form a single bond with the iodine atom. Therefore, there are 7 bonding pairs (I-F) in the molecule, accounting for a total of 14 electrons.
The remaining 42 valence electrons are used to complete the octet of each fluorine atom, leaving no electrons on iodine. Since there are no lone pairs on the central atom in IF₇, the sum of the number of lone pairs in IF₅ and IF₇ is 1 + 0 = 1.
Answer. 1

Answer 2

The correct answer is 0.1.00