Chapter 4: 4.1 Redox Reactions

“Redox” reactions Characterized by a change in the oxidation state of one or more elements in the reactants * When there is a net transfer of electrons from one reactant to another

One half-reaction where electrons are lost (donated)

One half-reaction where electrons are gained (received)

Oxidation Is Loss (OIL) Reduction Is Gain (RIG)

In a redox reaction: * The species that donates (or loses) electrons

False, it is oxidized

In a redox reaction: * The species that accepts (or gains) electrons

True

True

False, the number of electrons lost in the oxidation half-reaction must equal those gained in the reduction half-reaction

Used to facilitate the electron accounting in redox reactions

• In a pure element or elemental substance, oxidation state = 0 • Specific oxidation states to elements in a compound (separate flashcard) • Oxidation state = Charge on a monatomic ion • In a neutral species, oxidation state = 0 • In a complex ion, oxidation state = total charge on ion

In the following order: 1. Fluorine is always -1 2. Group 1 metals are +1 3. Group 2 metals are +2 4. Hydrogen is +1 (except when bounded to metal, it is -1) 5. Oxygen is usually -2 6. Other halogens are usually -1

• For C-O bonds, contributes +1 to the carbon • For C-H bonds, contributes -1 to the carbon • For C=O bonds, contributes +2 to the carbon • For C-C bonds, contribtues 0 to the carbon

A substance in an intermediate oxidation state goes to higher and lower states by electron transfer