Reactions of metals

• Reactivity of a metal

  How chemically reactive it is
• Metals with high reactivity

  • React very vigorously when added to water
  • Give off hydrogen gas
• Metals with low reactivity


  • Barely react with water or acid
  • Don't react at all
• Reactivity series


  Places metals in order of their reactivity
• Hydrogen and carbon are sometimes included in the reactivity series, even though they are non-metals
• Reactivity series


  • potassium
  • sodium
  • lithium
  • calcium
  • magnesium
  • aluminium
  • zinc
  • iron
  • lead
  • copper
  • silver
  • gold
• Reaction with water


  • Reacts very slowly
  • Fizzes, gives off hydrogen gas
  • Explodes
• Reaction with acid


  Reacts slowly with warm acid
• Extraction method


  Reduction with carbon
• Decreasing reactivity


  Metals are mined from the Earth's crust
• More reactive metal


  Displaces less reactive metal from its compounds
• Ionic equation


  An equation that shows the movement of ions
• Oxidation


  A substance gains oxygen in a reaction
• Reduction


  A substance loses oxygen in a reaction
• Reactivity


  The tendency of a substance to undergo chemical change
• Reactivity series


  The arrangement of elements in order of their reactivity
• Redox


  Reduction and oxidation occurring together in a reaction
• Metal extraction


  • Some metals like gold are so unreactive they are found as pure metals in the Earth's crust and can be mined
  • Most metals exist as compounds in rock and have to be extracted from the rock
  • If there is enough metal compound in the rock to be worth extracting it is called an ore
• Extracting less reactive metals

  1. Reduction with carbon

  2. For example: iron oxide + carbon -> iron + carbon dioxide
• Extracting more reactive metals

  Electrolysis
• Metals that are less reactive than carbon can be extracted by reduction with carbon
• Metals that are more reactive than carbon can be extracted using a process called electrolysis
• If a substance gains oxygen in a reaction


  It has been oxidised
• If a substance loses oxygen in a reaction

  It has been reduced
• Oxidation and reduction


  • iron + oxygen -> iron oxide
  • iron oxide + carbon -> iron + carbon dioxide
• Displacement reaction


  A more reactive element takes the place of a less reactive element in a compound
• Displacement reaction


  • copper sulfate + iron → iron sulfate + copper
• Iron is more reactive than copper, so iron displaces the copper in copper sulfate
• Reactivity of a metal

  Depends on how readily it forms an ion by losing electrons
• In the displacement reaction of copper sulfate and iron


  Iron forms an ion more easily than copper
• At the end of the reaction you are left with iron ions, not copper ions
• Iron is more reactive than copper, so iron displaces the copper in copper sulfate
• Ionic equations


  When an ionic compound is dissolved in a solution, we can write the compound as its separate ions
• Spectator ions


  Ions that are unchanged in the reaction and can be removed from the equation
• Steps for writing an ionic equation

  1. Check symbol equation is balanced

  2. Identify all aqueous ionic compounds

  3. Write those compounds out as ions

  4. Remove spectator ions
• Oxidation


  Loss of electrons
• Reduction


  Gain of electrons
• In the displacement reaction

  Iron atoms have been oxidised, copper ions have been reduced
• These two equations are called half equations - they each show half of the ionic equation
• What does reactivity mean?

  how vigorously a substance chemically reacts