1. Sources and Uses of Metals
Unit 2: Section B

2. Cu2+(liquid) + 2e- Cu (solid)
Reduction
Reduction – any chemical change in which a species gains one or more electrons
Happens when more reactive metals react with a less reactive metal ion
Example: Formation of Copper metal
Cu2+(liquid) + 2e- Cu (solid)
Cu ion must gain two electrons to become a neutral atom of copper metal.

3. Cu (solid) Cu2+(liquid) + 2e-
Oxidation
Oxidation – When a species loses one or more electrons
Historically refers to chemical combination of a substance with oxygen
Can happen with any chemical that causes a species to lose one or more electrons
Example: Formation of Copper ions
Cu (solid) Cu2+(liquid) + 2e-

4. Redox Oxidation Is Loss of electrons Reduction Gain of electrons
To Remember…
Oxidation Is
Loss of electrons
Reduction
Gain of electrons

5. Redox
In order for one species to gain an electron, another must lose an electron
Reduction always happens with oxidation
Called redox reactions (reduction and oxidation)

6. Cu(s) + 2 Ag+(aq) Cu2+(aq) + 2 Ag(s)
Redox
Example:
Cu(s) + 2 Ag+(aq) Cu2+(aq) + 2 Ag(s)
Metallic copper was oxidized (converted to Cu2+ by losing two electrons)
Silver ion was reduced (converted to metallic silver by gaining one electron)

7. How do Redox Reactions Occur?
Need to reduce many metallic elements because they are found in minerals as cations
Reducing agent – a reacting chemical species that serves as the source of electrons