(Solved): These formulas involve the use of a polyatomic ion. The cations are all of variable oxidation state ...

These formulas involve the use of a polyatomic ion. The cations are all of variable oxidation state, so Roman numerals are needed. Write the or: 11) \( \mathrm{Sn}\left(\mathrm{NO}_{3}\right)_{2} \) 12.) \( \mathrm{FePO}_{4} \) 13) \( \mathrm{Cu}_{2} \mathrm{SO}_{4} \) 14) \( \mathrm{Ni}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{2} \) 15) \( \mathrm{HgCO}_{3} \) 16) \( \mathrm{Pb}(\mathrm{OH})_{4} \) 17) \( \mathrm{Cu}_{2} \mathrm{CO}_{3} \) 18) \( \mathrm{Cu}\left(\mathrm{CH}_{3} \mathrm{COO}\right)_{2} \) 19) \( \mathrm{FeSO}_{4} \) 20) \( \mathrm{Co}(\mathrm{OH})_{2} \)