1. Oxidation State Rules

2. Rule # 1 - Free Elements The free element has an oxidation state = zero. The free element has an oxidation state = zero. H 2 H 2 O 2 O 2 Fe Fe Mg Mg C

3. Rule #2 - Compounds Compounds have a total oxidation state = zero. Compounds have a total oxidation state = zero. Examples: Examples: NaCl = 0NaCl = 0 CO 2 = 0CO 2 = 0

4. Rule #3 - Ions Ions (polyatomic ions) have an oxidation state equal to the charge on the ion. Ions (polyatomic ions) have an oxidation state equal to the charge on the ion. Examples: Examples: NO 2 -1NO 2 -1 NO 3 -1NO 3 -1 SO 3 -2SO 3 -2 SO 4 -2SO 4 -2 PO 4 -3PO 4 -3

5. Rule #4 - Alkalai Metals In compounds, Alkalai metals have an oxidation state = +1 In compounds, Alkalai metals have an oxidation state = +1 Na +1 Na +1 K +1 K +1 Rb +1 Rb +1

6. Rule #5 - Alkaline Earth Metals In compounds, Alkaline Earth metals have an oxidation state = +2 In compounds, Alkaline Earth metals have an oxidation state = +2 Ca +2 Ca +2 Mg +2 Mg +2 Ba +2 Ba +2

7. Rule #6 - Hydrogen In compounds, Hydrogen has an oxidation state = +1 In compounds, Hydrogen has an oxidation state = +1 H +1 H +1

8. Rule #7 - Fluorine In compounds, Fluorine has an oxidation state = -1 In compounds, Fluorine has an oxidation state = -1 F -1 F -1

9. Rule #8 - Oxygen In compounds, Oxygen has an oxidation state = -2 In compounds, Oxygen has an oxidation state = -2 O -2 O -2

10. Rule #9 – In Binary compounds, Group 17 = -1 Ex. Cl -1 Group 17 = -1 Ex. Cl -1 Group 16 = -2 Ex. S -2 Group 16 = -2 Ex. S -2 Group 15 = -3 Ex. N -3 Group 15 = -3 Ex. N -3

11. Rules of Precedence The rule higher in this list takes precedence or priority (ie. The rule with the lowest number in this list). The rule higher in this list takes precedence or priority (ie. The rule with the lowest number in this list). The element higher in the family takes precedence or priority (ie. The element with the lowest atomic number). The element higher in the family takes precedence or priority (ie. The element with the lowest atomic number).

12. Oxidation State Rules Rule #1 – The free element has an oxidation state = zero. Rule #1 – The free element has an oxidation state = zero. Rule #2 – Compounds have a total oxidation state = zero. Rule #2 – Compounds have a total oxidation state = zero. Rule #3 – Ions (polyatomic ions) have an oxidation state equal to the charge on the ion. Rule #3 – Ions (polyatomic ions) have an oxidation state equal to the charge on the ion. Rule #4 – Alkalai metals have an oxidation state = +1 Rule #4 – Alkalai metals have an oxidation state = +1 Rule #5 – Alkaline Earth metals have an oxidation state = +2 Rule #5 – Alkaline Earth metals have an oxidation state = +2 Rule #6 – Hydrogen in compounds has an oxidation state = +1 Rule #6 – Hydrogen in compounds has an oxidation state = +1 Rule #7 – Fluorine has an oxidation state = -1 Rule #7 – Fluorine has an oxidation state = -1 Rule #8 – Oxygen has an oxidation state = -2 Rule #8 – Oxygen has an oxidation state = -2 Rule #9 – In binary compounds, Rule #9 – In binary compounds, Group 17 = -1 Ex. Cl -1Group 17 = -1 Ex. Cl -1 Group 16 = -2 Ex. S -2Group 16 = -2 Ex. S -2 Group 15 = -3 Ex. N -3Group 15 = -3 Ex. N -3 Rules of Precedence or Priority Rules of Precedence or Priority The rule higher in this list takes precedence or priority. (ie. The rule with the lowest number in this list).The rule higher in this list takes precedence or priority. (ie. The rule with the lowest number in this list). The element higher in the family takes precedence or priority. (ie. The element with the lowest atomic number).The element higher in the family takes precedence or priority. (ie. The element with the lowest atomic number).