Redox reaction

• Oxidation

  Addition of oxygen to a substance
• Reduction


  Removal of oxygen from a substance
• Reduction and oxidation always take place together
• Redox reaction


  Reduction and oxidation
• In a redox reaction, some substances are oxidized and some are reduced
• Redox reaction


  Can be explained in terms of the gain or loss of electrons
• Magnesium burning in oxygen to form magnesium oxide


  1. Magnesium loses electrons (oxidation)

  2. Oxygen gains electrons (reduction)
• Oxidation


  Loss of electrons
• Reduction


  Gain of electrons
• OILRIG stands for: Oxidation Is Loss of electrons, Reduction Is Gain of electrons
• Half-equation


  Equation showing what happens to the electrons during oxidation and reduction
• Reactions of metals with acids are redox reactions
• In metal reactions with acids, H+ ions are reduced and the metal is oxidized
• In metal displacement reactions, the more reactive metal is oxidized and the less reactive metal is reduced
• Reactivity series

  • potassium
  • sodium
  • calcium
  • magnesium
  • aluminium
  • iron
  • nickel
  • copper
  • gold
  • tin
  • silver
  • zinc
  • lead
  • platinum
• Group 1 metals react with water to produce metal hydroxide and hydrogen gas
• Metals react with oxygen to form metal oxides
• Halogen displacement reactions


  The more reactive non-metal is reduced, the less reactive non-metal is oxidized
• Halogens in order of reactivity


  • Fluorine
  • Chlorine
  • Bromine
  • Iodine
• Halogen displacement reactions are redox reactions
• In the halogen displacement reaction, chlorine is reduced and bromide ions are oxidized