Question

Given the chemical formulas of the following compounds, name each compound and state the rules you used to determine each name.
• RbF
• CuO
• (NH4)2C2O4
(Note: C2O4– is called oxalate.)

Answer 1

RbF is an ionic compound between a metal and a nonmetal, so we just use the cation's name plus the anion's name with the "-ide" suffix:

1.) rubidium fluoride

CuO is also an ionic compound, but in this case we have a metal which can exist with multiple charges, so you must indicate the charge of the cation in the name. Since it's paired with oxygen, which has a -2 charge, the charge of the copper must balance it out since the molecule is net-neutral. So the copper must have a +2 charge:

2.) copper (ii) oxide

The third compound, (NH4)2C2O4 is a covalent molecule, so we just need to use the numbered prefix system (mono-, di-, tri-, etc.) to name it. We have two ammonium molecules bonded with one oxalate molecule:

3.) diammonium oxalate