Oxidation and Reduction
Subtitle
Definition
• Oxidation Reduction Reaction (Redox):
A reaction in which electrons are transferred
from one substance to another.
Definition of Redox Reaction
• Oxidation cannot occur without reduction
• Definition of Oxidized:
1. Losing of electrons (LEO)
2. Increasing the ox. number, ie: 0 to +1
Becoming more positive
-2 to -1
3. Gaining oxygen
• Definition of Reduced:
1. Gaining of electrons (GER)
2. Reducing the ox. number, ie: -1 to -2
Becoming more negative
1 to 0
3. Losing oxygen
•
LEO goes GER
Oxidation
Is
Losing
Reduction
Is
Gaining
Example of an electron transfer reaction
• 2Mg + O2  2MgO
• Mg atom transfers two electrons to each oxygen atom.
• As a result 2 Mg atoms become Mg2+ and two oxygen atoms
become O2• Mg loses two electrons
• O gains two electrons
Example of an electron transfer reaction
Examples of Oxidation Reduction
• When an electron is lost (An electron is found on
the product side) there is oxidation
• X0  X+1 + e• When an electron is gained (An electron is found on
the reactant side) there is reduction
• e- +Y+1  Y0
Examples:
start
• Ex5
• Ex6
• Ex7
• Ex8
finish
Na0Na+1 +1e-
1e-+ Fe+3Fe+2
N+1N+2 +1e-
2e-+ Mg+2Mg0
(LEO)oxidized
(GER)reduced
(LEO)oxidized
(GER)reduced
Vocabulary
• Whatever is oxidized is called the reducing agent
• Whatever is reduced is called the oxidizing agent
Real Examples:
start
• Ex5
• Ex6
• Ex7
• Ex8
finish
Na0Na+1
+1e-
1e-+ Fe+3Fe+2
N+1N+2 +1e-
2e-+ Mg+2Mg0
oxidized
reducing agent
reduced
oxidizing agent
oxidized
reducing agent
reduced
oxidizing agent