Question

Iodine in$I{F_7}$ is surrounded by 7 pairs of electrons yet it is stable.

Answer 1

: Iodine heptafluoride ($I{F_7}$), is an interhalogen compound, a compound formed by one halogen reacting with another halogen. The halogen-halogen bond in interhalogen compounds is weaker than that of bonds in dihalogen molecules.

Complete step by step answer:
Iodine heptafluoride ($I{F_7}$) or iodine (VII) fluoride, is formed by reaction between two halogens, iodine(I) and fluorine(F). This is $A{X_7}$ type of interhalogen compound, in which an atom is less electronegative than an X atom.
To understand the structure and geometry $I{F_7}$, we will need to consider VSEPR. VSEPR theory allows us to predict the geometry of different compounds based on the number of electron pairs present around the central atom of that compound.
The electronic configuration of iodine and fluorine is shown below.

Iodine $\left[ {Kr} \right]4{d^{10}}5{s^2}5{p^5}$

Fluorine $\left[ {He} \right]2{s^2}2{p^5}$

There are seven valence electrons in an iodine atom. According to Valence Shell Electron Pair Repulsion Theory (VSEPR), when $I{F_7}$ is formed each valence electron of iodine atom forms a bond with one fluorine atom. This results in formation of seven bond pairs, surrounding the central iodine atom. There is no lone pair of electrons surrounding the central iodine atom. Due to the absence of a lone pair of electrons in the valence shell of iodine in $I{F_7}$, the compound $I{F_7}$ is chemically inert and stable.
In $I{F_7}$, the central iodine atom undergoes $sp^3d^3$ hybridisation. As per VSEPR, if a molecule has seven bond electron pairs and zero lone pair of electrons, then the predicted geometry of the molecule is pentagonal bipyramidal.

So, the correct answer is Option A.

Note: Iodine heptafluoride is a colourless gas. It is prepared by reaction iodine pentafluoride with fluorine gas. : Iodine and fluorine belong to the Group VII, halogens. Halogens are extremely reactive in nature as they require only electron in their valence shell to complete their octet. Student should not be confused between the reactivity of iodine and fluorine in their gaseous form and chemical inertness of iodine heptafluoride.