This document provides instructions for writing formulas for ionic compounds based on the elements that react to form them. It lists common elements and their ions, and notes that the charges of the ions must equal zero to form a neutral compound. Examples are given of writing formulas by determining the ratio of ions that satisfies the neutral charge requirement.

1. Writing Formulas for Ionic Compounds Ch 8.3
For #s 1-10 Give the formula/ Compound formed using the given elements (Hint:
Look at the ions they form charges MUST = “0”)
Compound made of Ions Ratio Formula Name
1. hydrogen and sulfur
2. calcium and chlorine
3. sodium and
phosphorus
4. aluminum and sulfur
5. magnesium and
oxygen
6. aluminum and
chlorine
7. magnesium and
fluorine
8. sodium and sulfur
9. hydrogen and oxygen

2. Writing Formulas for Ionic Compounds Ch 8.3
10. aluminum and
oxygen
11. calcium and
phosphorus
12. calcium and oxygen