Before writing chemical formulas, students need to know how to interpret them. What do all the various symbols and numbers mean. This Powerpoint presentation explores concepts such as subscripts, coefficients, polyatomic ions, parentheses, and the dot. It explains how to use them, what they mean, and how to interpret formulas that have them. The lesson culminates with an example that has a complex combination of all the parts of a formula, and asks students to count the atoms.
Worksheets on this topic are available on my website at http://www.evanschemistrycorner.com.