reactivity series

• p- potassium

  s- sodium

  c- calcium

  m- magnesium

  c- carbon

  z- zinc

  i- iron

  l- lead

  H- hydrogen

  C- copper

  S- silver
• what is needed for rusting ?

  1. Water
  2. Oxygen
• speeding up the process of rusting

  1. Sodium chloride
  2. Acidic substances
  3. Carbon dioxide
• The more likely a metal atom is to lose electrons to form a positive ion, the more reactive the metal.
• metal + cold water ->metal hydroxide+ hydrogen

  metal + steam ->metal oxide +hydrogen
• potassium -> reacts very violently

  Sodium -> react violently

  Calcium -> reacts readily

  Magnesium -> reacts very slowly
• iron + oxygen + water → hydrated iron(III) oxide 4 Fe(s) + 3 O2(g) + 2𝐠H2O(l) → 2 Fe2O3𝑈•xH2O(s)
• Scratch

  The underlying iron may rust more quickly than if there was no coating
• Food cans, taps, kettles, bicycle handle bars

  • Electroplating
• Protective layer is peeled off, washed off or broken


  Oxygen and water can reach the iron and the exposed parts will rust
• Plastic coating

  Kitchenware such as draining racks
• Painting is cheap for large objects like cars, ships and bridges
• Electroplating is quite expensive
• Oiling of tools and machine parts


  • 
    
• Large objects

  • Cars, ships, bridges
• Electroplating

  Nice appearance, with rust protection
• Use of protective layer Working principle: The layer acts as a barrier that prevents the iron from coming into contact with oxygen and water.
• The presence of both oxygen (in air) and water are necessary for rusting to occur. • The presence of sodium chloride increases the speed of rusting. • The presence of acidic substances, such as sulfur dioxide and carbon dioxide will also increase the speed of rusting. • Thus, iron objects near the sea and in industrial areas corrode more rapidly because of the presence of salt and other pollutants in the air.
• bridges can become unsafe and need to be replaced for safety reasons.
• (most reactive) barium > calcium > iron > tin > copper (least reactive)
• Metals which are very unreactive are found naturally uncombined as a metal. (Gold)
• Less reactive metals are extracted by heating the metal oxides using carbon, carbon monoxide/ hydrogen(ZILCS)
• Highly reactive metals are extracted by electrolysis (pscm)