Copyright © 2008 Pearson Prentice Hall, Inc.
Chapter 7/
11
Electron-Dot Structures of
Polyatomic Molecules
Step 1: Valence Electrons
•
Count the total number of valence electrons for
all atoms in the molecule.
•
Add one additional electron for each negative
charge in an anion or subtract one for each
positive charge in a cation.
The rules seem arbitrary to students.
They have been developed in order to get to a finished structure.