3. Balanced! Formula is: KCl

4. Ca 2+ Formula is: CaBr 2 Br - Not balanced! 1(2+) + 2(1 - ) = 0

5. Ca 2+ S 2- Formula is: Ca 2 S 2 Reduce!! Formula is: CaS Correct!!

6. If an element forms more than one ion, a Roman numeral is used to indicate the charge

7. Zinc = Zn 2+ Silver = Ag + No Roman numeral is used for elements that have only one oxidation state

8. Fe 3+ O 2- Not balanced! Formula is: Fe 2 O 3 2(3+) + 3(2-) = 0

9. Fe 3+ O 2- Fe 2 O 3

13. Ca 2+ NO 3 - Ca ( NO 3 ) 2

14. Li + CO 3 2- Li 2 CO 3

15. Mg 2+ OH - Mg(OH) 2

17. sodium iodide

18. copper(II)oxide