How to write formulas for chemical compounds

Ionic Compounds (Metal, possibly with a Roman numeral + Non-metal)

1 - Get the symbols and charges for each element in the compound. 2 - Crisscross charges.

Ionic Compounds (Metal, possibly with Roman numeral + Polyatomic Ion)

1 - Get the symbols and charges for each element in the compound. 2 - Crisscross charges. 3 - Add parentheses, if needed, to the polyatomic ions to separate the subscripts.

Covalent Compounds (Non-metal + Non-metal)

1 - look at the prefixes. 2 - depending on the prefixes, add subscripts.

Binary Acids (hydrogen + element)

1 - look at the element. 2 - add the prefix hydro- and the suffix -ic, and the word “acid”.

Oxyacids (hydrogen + polyatomic ions)

1 - Look at the ending suffix of the polyatomic ion. 2 - if it’s -ate you add -ic, if it’s -ite you add -ous.