Sources and Uses of Metals Unit 2: Section B

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.

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-

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

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)

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)

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