Draw the Lewis structures of the molecules below, and use them to answer the following questions.
I. BH₃
II. NO₂
III. SF₆
IV. O₃
V. PCl₅
How many of the molecules have no dipole moment?

Question

Quizplus · Accepted Answer

In order to determine if a molecule has a dipole moment, we need to examine the electronegativities and geometry of the atoms. If the molecule has polar bonds (meaning there is a difference in electronegativity between the atoms in the bond), we then need to determine if the geometry of the molecule results in an overall dipole moment.

Using this approach, we can see that molecules I, II, III, and V all have polar bonds and a geometry that results in an overall dipole moment. However, in molecule IV, the polar bonds are oriented in such a way that they cancel each other out, resulting in a molecule with no dipole moment. Therefore, the answer is D, three of the molecules have no dipole moment.

Draw the Lewis Structures of the Molecules Below, and Use