Electrolysis

• The reactivity of metals depends on their ability to lose electrons and form a positive ion
• Using reactions between metals and water

  Constructing a reactivity series
• Metals react by

  Losing electrons and forming a positive ion
• Metals at the top of the reactivity series readily form a positive ion, while metals towards the bottom are much less likely to do so
• Using reactions between metals and acids

  Determining reactivity of metals
• Oxidation

  Gaining oxygen in a reaction
• More reactive element displaces less reactive element


  More reactive element pushes out or displaces a less reactive element from its compound
• Metal extraction using carbon


  1. Active metals like gold are found in the earth as the metal itself due to being unreactive

  2. Metals like copper are found in the Earth's crust as oxides, formed by reacting with oxygen. The challenge is to extract the metal from these compounds
• In the reaction between carbon and iron oxide, iron is reduced as it loses oxygen, while carbon is oxidized as it gains oxygen
• In practice, carbon is used for metal extraction as it is cheap and can displace many metals
• Reduction

  Losing oxygen in a reaction
• Reactivity series

  Elements ordered from most reactive to least reactive, where more reactive elements can displace less reactive elements from their compounds
• Reaction between magnesium and iron oxide

  • Magnesium displaces iron from iron oxide, producing magnesium oxide and iron
• electrolysis is the breakdown of a compound by an electric current
• We can use electrolysis to extract valuable metals from their ores in the ground
• Potassium + water --> Potassium hydroxide + hydrogen
• Metal + water --> metal hydroxide + hydrogen
• When metals react they lose electrons and form a positive ion