Molecular Geometry And Chemical Bonding Theory Worksheet With Answers

Molecular Geometry And Chemical Bonding Theory Worksheet With Answers - Chapter 10

Chapter 10

Molecular Geometry and

Chemical Bonding Theory

Concept Check 10.1

An atom in a molecule is surrounded by four pairs of electrons, one lone pair and three

bonding pairs. Describe how the four electron pairs are arranged about the atom. How are any

three of these pairs arranged in space? What is the geometry of this atom plus the three

bonded to it?

Solution

The VSEPR model predicts that four electron pairs about any atom in a molecule will

distribute themselves to give a tetrahedral arrangement. Any three of these electron pairs

would have a trigonal pyramidal arrangement. The geometry of a molecule having a central

atom with three atoms bonded to it would be trigonal pyramidal.

Concept Check 10.2

Two molecules, each with the general formula AX

, have different dipole moments. Molecule

Y has a dipole moment of zero, whereas molecule Z has a nonzero dipole moment. From this

information, what can you say about the geometries of Y and Z?

Solution

A molecule AX

could have one of three geometries: it could be trigonal planar, trigonal

pyramidal, or T-shaped. Assuming that the three groups attached to the central atom are alike,

as indicated by the formula, the planar geometry should be symmetrical, so that even if the

A—X bonds are polar, their polarities would cancel to give a nonpolar molecule (dipole

moment of zero). This would not be the case in the trigonal pyramidal geometry. In this

Molecular Geometry And Chemical Bonding Theory Worksheet With Answers - Chapter 10