Oxidation and Reduction Reactions

Oxidation

reactant atoms lose e-

Reduction

reactant atoms gain e-

Oxidation-reduction reaction

reaction where e- are transferred from reactant to another

Oxidation number (ON)

increases in oxidation

decreases in reduction

1. The oxidation number of an element

is zero

2. If something is ionic, the charges

= ON

3. Leading elements always have a set oxidation number:

a. Group 1 =

b. Group 2 =

c. Fluorine = -1

+1

+2

-1

4. Hydrogen in a compound (unless with a metal)

without metal = +1

with metal = -1

5. Oxygen in a compound (unless in a molecule with a leading element or hydrogen)

without leading element/hydrogen = -2

with leading element/hydrogen = solve algebraically

6. The sum of the oxidation numbers in a compound

is equal to zero

6. in a polyatomic ion

is equal to the charge of the ion

7. Element on the right in a molecular formula (or polyatomic ion), negative charge =

column #

7. Any other unknown elements ON’s =

in order of decreasing EN

Half reactions

two reactions showing movement of e- from an oxidation reduction reaction

Combustion

hydrocarbon + oxygen → carbon gas + steam

Combination

2+ compounds → 1 product

Decomposition

1 reactant → 2 products

Precipitation

______(aq) + _____(aq) → _____(s)

Acid-base

acid + base → H₂O

Oxidation reduction

metal becomes oxidized (+___)