1. Oxidation States Unit 8 1

2. Oxidation States 2 Goal: Identify if a reaction is a redox reaction Oxidation State: The charge that an atom appears to have Common sense usually prevails when assigning oxidation states Rules for assigning oxidation state 1.The oxidation number of ANY element in its most stable form is ALWAYS 0. Examples: Fe(s), O 2, Cl 2, F 2, N 2, C(s) 2.If monoatomic ions appear in the equation (e.g. Na + ), the charge is the oxidation state. 3.Group IA = +1 and Group IIA = +2. 4.Halogens are usually -1. 5.Oxygen is usually -2. Exceptions: O 2 = 0 and H 2 O 2 = -1. 6.Hydrogen is usually +1. Exceptions: H 2 = 0 and when bonded to a metal (NaH) = -1. 7.Binary Compounds: most electronegative has its charge as an anion (e.g. F = -1, O = -2, etc.) and cation balances the charge

3. Oxidation State 3 Rules for assigning oxidation state 1.The oxidation number of ANY element in its most stable form is ALWAYS 0. Examples: Fe(s), O 2, Cl 2, F 2, N 2, C(s) 2.If monoatomic ions appear in the equation (e.g. Na + ), the charge is the oxidation state. 3.Group IA = +1 and Group IIA = +2. 4.Halogens are usually -1. 5.Oxygen is usually -2. Exceptions: O 2 = 0 and H 2 O 2 = -1. 6.Hydrogen is usually +1. Exceptions: H 2 = 0 and when bonded to a metal (NaH) = -1. 7.Binary Compounds: most electronegative has its charge as an anion (e.g. F = -1, O = -2, etc.) and cation balances the charge Cl 2 FeH 2 CH 2 ONH 3 NH 4 +

4. Oxidation State 4 Rules for assigning oxidation state 1.The oxidation number of ANY element in its most stable form is ALWAYS 0. Examples: Fe(s), O 2, Cl 2, F 2, N 2, C(s) 2.If monoatomic ions appear in the equation (e.g. Na + ), the charge is the oxidation state. 3.Group IA = +1 and Group IIA = +2. 4.Halogens are usually -1. 5.Oxygen is usually -2. Exceptions: O 2 = 0 and H 2 O 2 = -1. 6.Hydrogen is usually +1. Exceptions: H 2 = 0 and when bonded to a metal (NaH) = -1. 7.Binary Compounds: most electronegative has its charge as an anion (e.g. F = -1, O = -2, etc.) and cation balances the charge NO 2 - NO 3 - CH 4 CCl 4

5. Oxidation State 5 Rules for assigning oxidation state 1.The oxidation number of ANY element in its most stable form is ALWAYS 0. Examples: Fe(s), O 2, Cl 2, F 2, N 2, C(s) 2.If monoatomic ions appear in the equation (e.g. Na + ), the charge is the oxidation state. 3.Group IA = +1 and Group IIA = +2. 4.Halogens are usually -1. 5.Oxygen is usually -2. Exceptions: O 2 = 0 and H 2 O 2 = -1. 6.Hydrogen is usually +1. Exceptions: H 2 = 0 and when bonded to a metal (NaH) = -1. 7.Binary Compounds: most electronegative has its charge as an anion (e.g. F = -1, O = -2, etc.) and cation balances the charge Cr 2 O 7 2- CrO 4 2-