Practice!

Sample Problem

Which of the following compound names are correct?

Fe(ClO3)2…iron (III) chlorate

SnCrO4…tin (II) chromate

Cr(CO3)2…chromium (IV) carbonate

 Cu(NO3)2…copper (II) nitrate

Ni(C4H6O4)2…nickel (IV) acetate

Solution

The Roman numeral for transition metals generally equals the total negative charge of the anion atom or polyatomic compound. For tin (II) chromate, the total anion charge is -2, so tin has a cation charge of +2 (use the Roman numeral II). For chromium carbonate, the total anion charge is -4, so chromium has a cation charge of +4 (use the Roman numeral IV).