Question

Which of the following best describes ICl₂-? It has a molecular geometry that is

A) linear molecular shape with no lone pairs on the I atom.

B) linear molecular shape with lone pairs on the I atom.

C) non-linear molecular shape with no lone pairs on the I atom.

D) non-linear molecular shape with lone pairs on the I atom.

Answer 1

Concepts and reason

The concept involved here is the Valence Shell Electron Pair Repulsion theory.

The VSEPR theory is useful in predicting molecular geometries.

Fundamentals

The VSEPR theory explains and predicts the shapes of molecules and ions based on the number of electron pairs present around the central atom. These electron pairs repel each other, and hence, adopt a geometry that minimizes the repulsions between electron pairs.

For predicting the geometry of molecules, the number of electron pairs (bonding and lone pairs) is counted. The repulsion between thelone pairs is.more than the bond pairs. The number of lone pairs together with bond pairs determines the shapeof a molecule. The order of the repulsions between the lone pairs and bond pair is as follows:

${\rm{lone pair}} - {\rm{lone pair}} > {\rm{lone pair}} - {\rm{bond pair}} > {\rm{bond pair}} - {\rm{bond pair}}$

Consider the Lewis structure of ${\rm{IC}}{{\rm{l}}_2}^ -$ .

So, there are five electron pairs around the central iodine atom, two bond pairs, and three lone pairs.

The ideal five electron pairs consisting of only bond pairs give a trigonal bipyramidal structure. There are three lone pairs in ${\rm{IC}}{{\rm{l}}_2}^ -$ .

The lone pairs occupy the three equatorial positions minimizing the repulsion between them and leaving the axial positions for chlorine atoms. Therefore, the geometry of the molecule is linear.

Hence, the correct statement is option B) linear molecular shape with lone pairs on the iodine $\left( {\rm{I}} \right)$ atom.

Ans:

${\rm{IC}}{{\rm{l}}_2}^ -$ has linear molecular shape with lone pair of electrons on ${\rm{I}}$ atom.