Solutions to Exercises VSEPR

Exercises

Exercise 1. Predict both the electron pair geometry and shape of SbF₅^–.

First draw the Lewis structure.

There are 6 charge clouds, and the electron pair geometry is octahedral. There is one lone pair and the molecular geometry is square pyramidal.

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Exercise 2. Predict both the electron pair geometry and shape of SO₂Cl₂.

First draw the Lewis structure.

There are 4 charge clouds and zero lone pairs on the sulfur atom. Both the electron pair and molecular geometries are tetrahedral.

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Exercise 3. What shape would you predict for the following ions?

a) XeF₃⁺

First draw the Lewis structure.

There are 5 charge clouds (an octahedral electron pair geometry), but two of those are lone pairs of electrons. The molecular shape is t-shape.

b) SCN^–

First Draw the Lewis structure.

The shape is linear. There are 2 charge clouds and zero lone pairs on carbon.

c) CrO₄^2-

First, draw the Lewis structure.

The chromate ion has a tetrahedral shape with 4 bonds and zero lone pairs.

d) ClO₃^–

Draw the Lewis Structure

There are 4 charge clouds but one of them is a lone pair of electrons. The shape of the ion is trigonal pyramidal.

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Exercise 4. What is the electron pair geometry and the shape of SO₃?

Draw the Lewis structure.

There are three charge clouds. The electron pair geometry is trigonal planar. There are 3 bonds with zero lone pairs, and the molecular geometry is trigonal planar.

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Exercise 5. What are the bond angles in PH₃?

Draw the Lewis structure.