C5 - Chemical changes

• Reactions of metals


  • The reactivity of a metal is how chemically reactive it is
  • When added to water, some metals react vigorously
  • These metals have high reactivity
  • Other metals barely react with water or acid at all
  • These metals have low reactivity
• Reactivity series


  • The reactivity series places metals in order of relative reactivity
  • Sometimes hydrogen and carbon are included in the series
• The reactivity series - high to low

  • Potassium
  • Sodium
  • Lithium
  • Calcium
  • Magnesium
  • Aluminium
  • [carbon]
  • zinc
  • iron
  • tin
  • lead
  • [hydrogen]
  • copper
  • silver
  • gold
• Extraction methods 


  • potassium to aluminium - electrolysis
  • zinc to copper - reduction with carbon
  • silver and gold - mined from the Earth's crust
• Reactions with acid


  • potassium to lithium - explodes
  • calcium to iron - fizzes, gives off hydrogen gas
  • tin and lead - reacts slowly with warm acid
  • copper to gold - no reaction
• Reactions with water

  • potassium to calcium - fizzes, gives off hydrogen gas
  • magnesium to iron - reacts very slowly
  • tin to gold - no reaction
• Metal extraction


  • Some metals are so unreactive that they can be found in the Earth's core
  • Most metals exist as compounds in rock and have to be extracted
  • If there is enough metal compound in the rock to be worth extracting, it is called ore
  • Metals that are less reactive than carbon can be extracted by reduction with carbon
• If a substance gains oxygen in a reaction, it has been oxidised
• If a substance loses oxygen in a reaction, it has been reduced
• Displacement reactions


  • In a displacement reaction, a more reactive element takes the place of a less reactive element in a compound
• Reactivity and ions


  • A metal's reactivity depends on how readily it forms an ion by losing electrons
• Steps for writing an ionic equation


  • check symbol equation is balanced
  • identify all aqueous ionic compounds
  • write those compounds out as ions
  • remove spectator electrons