Oxidation Numbers Worksheet

Directions: Use the Rules for Assigning Oxidation Numbers to determine the oxidation number assigned to each element in each of the given chemical formulas.

Formula / Element and Oxidation Number / Formula / Element and Oxidation Number
1. / Cl2 / Cl / 17. / Na2O2 / Na / O
2. / Cl- / Cl / 18. / SiO2 / Si / O
3. / Na / Na / 19. / CaCl2 / Ca / Cl
4. / Na+ / Na / 20. / PO43- / P / O
5. / O2 / O / 21. / MnO2 / Mn / O
6. / N2 / N / 22. / FeO / Fe / O
7. / Al+3 / Al / 23. / Fe2O3 / Fe / O
8. / H2O / H / O / 24. / H2O2 / H / O
9. / NO3- / N / O / 25. / CaO / Ca / O
10. / NO2 / N / O / 26. / H2S / H / S
11. / Cr2O72- / Cr / O / 27. / H2SO4 / H / S / O
12. / KCl / K / Cl / 28. / NH4Cl / N / H / Cl
13. / NH3 / N / H / 29. / K3PO4 / K / P / O
14. / CaH2 / Ca / H / 30. / HNO3 / H / N / O
15. / SO42- / S / O / 31. / KNO2 / K / N / O
16. / VO / V / O / 32. / KClO4 / K / Cl / O
Formula / Element and Oxidation Number / Formula / Element and Oxidation Number
F2 / F / Na2O / Na / O
F- / F / PO4-3 / P / O
Ba / Ba / N2O3 / N / O
Ba+2 / Ba / PO43- / P / O
O3 / O / MnO4 / Mn / O
H2 / N / Fe 2O3 / Fe / O
Fe+3 / Fe / SnO / Sn / O
CH4 / C / H / SnO2 / Sn / O
CO3-2 / C / O / OF2 / O / F
CO2 / C / O / NH4+1 / N / H
N2O5 / N / O / H2SO3 / H / S / O
Li4C / Li / C / (NH4)2S / N / H / S
SO3 / S / S / Li3PO4 / Li / P / O
CaO / Ca / O / HNO2 / H / N / O
SO32- / S / O / KClO2 / K / Cl / O
ClO21- / Cl / O / K2Cr2O7 / K / Cr / O
ClO1- / Cl / O / UO2F2 / U / O / F
ClO31- / Cl / O / Al2(SO4)3 / Al / S / O