Like all chemistry teachers, I dreaded the compounds unit because students always forgot which rules to apply when writing a chemical formula! I made this handout for students to practice writing chemical formulas AFTER the students learned how to write molecular, ionic, and acidic formulas.
Rather than just hand this flowchart to students, you may wish to delete some or all text and have students write formula directions in their own words. Or delete the questions and have students work in small groups to decide what the questions must be to lead to each formula directions.
Either way, many students will need someone to show them how to start and follow the flowchart.