1. Oxidation Numbers
HV2O4-  V6+
Is the above equation oxidation or reduction?
Oxidation numbers are used to quickly determine if oxidation or reduction has occurred in a redox reaction.

2. Rules for Oxidation Numbers Oxidation #
1. All elements are zero:

3. Rules for Oxidation Numbers Oxidation #
1. All elements are zero: N2

4. Rules for Oxidation Numbers Oxidation #
1. All elements are zero: N

5. Rules for Oxidation Numbers Oxidation #
1. All elements are zero: N Pb

6. Rules for Oxidation Numbers Oxidation #
1. All elements are zero: N Pb

7. Rules for Oxidation Numbers Oxidation #
1. All elements are zero: N Pb Na

8. Rules for Oxidation Numbers Oxidation #
1. All elements are zero: N Pb
Na 0

9. Rules for Oxidation Numbers Oxidation #
1. All elements are zero: N Pb
Na 0 O2

10. Rules for Oxidation Numbers Oxidation #
1. All elements are zero: N Pb
Na 0 O

11. Rules for Oxidation Numbers Oxidation #
2. Ions are their charge
Na+

12. Rules for Oxidation Numbers Oxidation #
2. Ions are their charge Na

13. Rules for Oxidation Numbers Oxidation #
2. Ions are their charge Na
Br-

14. Rules for Oxidation Numbers Oxidation #
2. Ions are their charge Na Br

15. Rules for Oxidation Numbers Oxidation #
2. Ions are their charge Na Br
MgSO4

16. Rules for Oxidation Numbers Oxidation #
2. Ions are their charge Na Br
MgSO

17. Rules for Oxidation Numbers Oxidation #
2. Ions are their charge Na Br
MgSO
Al2O3

18. Rules for Oxidation Numbers Oxidation #
2. Ions are their charge Na Br
MgSO
Al2O

19. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2.
Na2O

20. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2.
Na2O

21. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2.
Na2O
CO2

22. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2.
Na2O CO

23. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2.
Na2O CO O2

24. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2.
Na2O CO O

25. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2.
Na2O CO O
CH3COOH

26. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2.
Na2O CO O
CH3COOH -2

27. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2 or in
peroxides -1.
Na2O CO O
CH3COOH -2
HOOH

28. Rules for Oxidation Numbers Oxidation #
3. The oxidation number of O
in a compound is –2 or in
peroxides -1.
Na2O CO O
CH3COOH -2
HOOH -1

29. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1.

30. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1.
H2O

31. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1.
H2O

32. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1
H2O
C12H24O11

33. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1
H2O
C12H24O

34. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1
H2O
C12H24O H2

35. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1
H2O
C12H22O H

36. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1 or in
metal hydrides -1.
H2O
C12H24O H
NaH

37. Rules for Oxidation Numbers Oxidation #
4. The oxidation number for H
in a compound is +1 or in
metal hydrides -1.
H2O
C12H24O H
NaH

38. Oxidation # SO42- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
SO42-

39. Oxidation # oxidation #s SO42- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
SO42-

40. Oxidation # oxidation #s -2 SO42- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
SO42-

41. Oxidation # oxidation #s -2 SO42- Total charge
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
SO42-
Total charge

42. Oxidation # oxidation #s -2 SO42- Total charge -8
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
SO42-
Total charge

43. Oxidation # oxidation #s -2 SO42- Total charge -8 = -2
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
SO42-
Total charge = -2

44. Oxidation # oxidation #s -2 SO42- Total charge +6 -8 = -2
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
SO42-
Total charge = -2

45. Oxidation # oxidation #s +6 -2 SO42- Total charge +6 -8 = -2
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
SO42-
Total charge = -2

46. Oxidation # oxidation #s +6 -2 +6 SO42- Total charge +6 -8 = -2
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
SO42-
Total charge = -2

47. Oxidation # PO43- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
PO43-

48. Oxidation # oxidation #s PO43- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
PO43-

49. Oxidation # oxidation #s -2 PO43- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
PO43-

50. Oxidation # oxidation #s -2 PO43- Total charge
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
PO43-
Total charge

51. Oxidation # oxidation #s -2 PO43- Total charge -8
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
PO43-
Total charge

52. Oxidation # oxidation #s -2 PO43- Total charge -8 = -3
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
PO43-
Total charge = -3

53. Oxidation # oxidation #s -2 PO43- Total charge +5 -8 = -3
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
PO43-
Total charge = -3

54. Oxidation # oxidation #s +5 -2 PO43- Total charge +5 -8 = -3
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
PO43-
Total charge = -3

55. Oxidation # oxidation #s +5 -2 +5 PO43- Total charge +5 -8 = -3
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
PO43-
Total charge = -3

56. Oxidation # Cr2O72- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
Cr2O72-

57. Oxidation # oxidation #s Cr2O72- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Cr2O72-

58. Oxidation # oxidation #s -2 Cr2O72- Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Cr2O72-

59. Oxidation # oxidation #s -2 Cr2O72- Total charge
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Cr2O72-
Total charge

60. Oxidation # oxidation #s -2 Cr2O72- Total charge -14
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Cr2O72-
Total charge

61. Oxidation # oxidation #s -2 Cr2O72- Total charge -14 = -2
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Cr2O72-
Total charge = -2

62. Oxidation # oxidation #s -2 Cr2O72- Total charge +12 -14 = -2
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Cr2O72-
Total charge = -2

63. Oxidation # oxidation #s -2 Divide by 2 Cr2O72-
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Divide by Cr2O72-
Total charge = -2

64. Oxidation # oxidation #s +6 -2 Cr2O72- Total charge +12 -14 = -2
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Cr2O72-
Total charge = -2

65. Oxidation # oxidation #s +6 -2 +6 Cr2O72- Total charge +12 -14 = -2
Rules for Oxidation Numbers
5. All other oxidation numbers are assigned so that the sum of all of the oxidation numbers is equal to the charge on the chemical species.
Oxidation #
oxidation #s
Cr2O72-
Total charge = -2

66. Oxidation #
Ca(NO3)2

67. Oxidation # +2
Ca(NO3)2

68. Oxidation # +2
Ca(NO3)

69. Oxidation #
Na2C2O4

70. Oxidation #
Na2C2O4
= 0

71. Oxidation #
Na2C2O4
= 0

72. Oxidation #
Na2C2O
= 0

73. Oxidation #
CH3COOH

74. Oxidation #
Rewrite
C2H4O2

75. Oxidation #
Rewrite
C2H4O2
+4 -4 = 0

76. Oxidation #
Zn(OH)42-

77. Oxidation #
Zn(OH)42-
= -2

78. Oxidation #
H2PtCl6

79. Oxidation #
H2PtCl6
= 0

80. Oxidation #
Al(NO3)3

81. Oxidation #
Al(NO3)3
= 0

82. Oxidation #
H3PO3

83. Oxidation #
H3PO3
= 0

84. Oxidation #
Na2O2

85. Oxidation #
Na2O2
= 0
Exception - does not work, O must be -1

86. Oxidation #
Na2O2
= 0
Exception - does not work, O must be -1

87. Oxidation #
CaH2

88. Oxidation #
CaH2
= 0
Exception - does not work, H must be -1

89. Oxidation #
CaH2
= 0
Exception - does not work, H must be -1

90. Oxidation #
Fe(H2O)5(OH)2+

91. Oxidation # 0 -1 Fe(H2O)5(OH)2+ Water has a charge of 0
Fe(H2O)5(OH)2+
Water has a charge of 0
OH has a charge of -1

92. Oxidation #
Fe(H2O)5(OH) ? = +2

93. Oxidation #
Fe(H2O)5(OH) ? = +2

94. Oxidation Numbers
HV2O4-  V6+
Is the above equation oxidation or reduction?

95. Oxidation Numbers
+3 
HV2O4-  V6+
Is the above equation oxidation or reduction?

96. Oxidation Numbers
Increase
+3 
HV2O4-  V6+
Is the above equation oxidation or reduction?
If the oxidation number increases it is oxidation.