1. REDOX REACTIONS

2. A process in which a substance loses one or more electrons
OXIDATION
A process in which a substance loses one or more electrons

3. A process in which a substance gains one or more electrons
REDUCTION
A process in which a substance gains one or more electrons

4. Oxidation Is Losing electrons Reduction Is Gaining electrons
OIL RIG
Oxidation Is Losing electrons
Reduction Is Gaining electrons

5. Oxidation and reduction always occur together!

6. OXIDATION-REDUCTION RXNS
Reactions in which electrons are transferred between reactants
(bka Redox Reactions)

7. The key to Redox is Oxidation Number!

8. A way of tracking electrons in redox reactions
OXIDATION NUMBERS
A way of
tracking
electrons in
redox reactions

9. Assigning Oxidation Numbers (6 rules)

10. The oxidation # of an atom by itself is zero.
Rule 1
The oxidation # of an atom by itself is zero.

11. The oxidation # of any monatomic ion is equal to its charge.
Rule 2
The oxidation # of any monatomic ion is equal to its charge.

12. The oxidation # of elements in a compound are written per atom.
Rule 3
The oxidation # of elements in a compound are written per atom.

13. The sum of the oxidation #s in a compound is zero.
Rule 4
The sum of the oxidation #s in a compound is zero.

14. Rule 5 The sum of the oxidation #s in a polyatomic ion is
equal to the ion’s charge.

15. Oxidation #s to remember:
Rule 6
Oxidation #s to remember:
Elements in Group 1A: always +1
Elements in Group 2A: always +2
Aluminum: always +3

16. Oxidation #s to remember:
Rule 6
Oxidation #s to remember:
Fluorine: always -1
Hydrogen: usually +1
Oxygen: usually -2

17. Remember: Oxidation #s are not charges
Remember: Oxidation #s are not charges! (they are just a way to track electrons)

18. Oxidation: when the oxidation # increases
Another Definition
Oxidation:
when the
oxidation #
increases

19. Reduction: when the oxidation # decreases
Another Definition
Reduction:
when the
oxidation #
decreases

20. Remember that oxidation and reduction occur together…

21. Causes oxidation Is itself reduced
Oxidizing Agent
Causes oxidation
Is itself reduced

22. Causes reduction Is itself oxidized
Reducing Agent
Causes reduction
Is itself oxidized