23.1 Redox reactions

• A redox reaction always has an oxidising agent and reducing agent
• The oxidising agent

  • takes electrons away from the atom that is oxidised
  • is reduced
• The reducing agent

  • adds electrons to the atom that is reduced
  • is oxidised
• A redox equation can be written from the half-equations for reduction and oxidation
• In a balanced equation for a redox reaction

  number of electrons lost = number of electrons gained
• A redox equation can be written from oxidation numbers
• In a balanced equation for a redox reaction

  • increase in oxidation number = decrease in oxidation number