1.       Write the metal’s symbol or ammonium’s formula as the first part of the formula.

2.       Obtain the charge for the metal from the periodic table or from the Roman numeral in the name.

3.       Write the second part of the formula based on the ending

Ide – write nonmetal symbol or hydroxide formula

Ate/Ite – write the polyatomic ion formula

4.       Obtain the charge for the second part from either the periodic table or from the polyatomic ion’s charge.

5.       Swap and drop charges to get subscripts (ignore + and – .) Write polyatomic ions in parenthesis, if it gets an additional subscript.

6.       Things to watch for:

Reduce subscripts to simplest form

Calcium chloride  CaCl₂

Lithium sulfate  Li₂SO₄

Magnesium nitrate  Mg(NO₃)₂

Iron (III) Oxide Fe₂O₃