Ch 13 Reactivity Series

• Reactivity series

  metals arranged from most reactive to least reactive

  order is determined by reactions of metals with cold water, steam, dilute hydrochloric acid
• Metal + steam -> metal oxide + hydrogen
• order of reactivity

  Potassium

  Sodium

  Calcium

  Magnesium

  Carbon

  Zinc

  Iron

  Lead

  Hydrogen

  copper

  silver
• metal with cold water

  Potassium -> very violently

  sodium -> violently

  calcium -> readily

  Magnesium -> very slowly

  Carbon, zinc, iron, lead, copper, silver -> no reaction
• metal with steam

  potassium, sodium, calcium -> react explosively

  magnesium -> react violently, bright white glow

  carbon, Zinc -> readily, zinc oxide yellow when hot, and white when cold

  iron -> slowly

  lead, hydrogen, copper, silver -> no reaction
• metal + water -> hydroxide + hydrogen
• Metal and dilute hydrochloric acid

  Potassium, sodium -> react explosively

  Calcium -> violently

  magnesium -> rapidly

  carbon -> fast

  Zinc -> moderately fast

  Iron -> slowly

  lead, hydrogen, copper, silver -> no reaction
• metals below carbon can be reduced by carbon

  ->lower metal is in reactivity series from carbon, more readily the reduction of the metal oxide
• metal oxides below iron can be reduced by hydrogen

  oxides of iron will require highest temperature for reduciton
• more reactive metal has greater tendency to form positive ions compared to less reactive metal
• more reactive metal can displace a less reactive metal from salt solution
• redox reaction

  when more reactive metal oxidised while less reactive metal is reduced
• more reactive metal can reduce oxide of less reactive metal
• more reactive metals form ions more readily while unreactive metals tend to remain as atoms
• electrolysis -> extracts metals higher than carbon in reactivity series

  reduction with carbon -> extracts metals less reactive than carbon by reducing oxides with carbon
• rusting conditions

  iron object presence of both oxygen and water
• barrier methods -> keeping iron and steel away from oxygen and water

  Painting -> large objects

  oiling/greasing -> machinery

  coating with plastic -> smaller objects
• sacrificial protection -> using more reactive metals to react in place of iron or steel

  galvanizing -> thin layer of zinc coated onto object to keep iron and steel away from oxygen and moisture

  Attaching more reactive metal -> attach to iron or steel object so more reactive metal corrodes instead of iron or steel
• rusting as special case of corrosion


  when other metals than iron or steel corrode, oxide layer forms protective coating, thus preventing futher reaction
• Metal Carbonates impact by heating

  Potassium, sodium -> unaffected -> thermal stability high

  Calcium to copper -> decompose into metal oxide and carbon dioxide on heating

  Silver -> decomposes into silver and carbon dioxide
• more reactive metal -> higher thermal stability -> more difficult to decompose
• Gold, platinum occur naturally as uncombined, very unreactive metals
• the more reactive the metal is, the harder it is to extract the metal from its ore
• other conditions of rusting that speed up rate of rusting

  Presence of acidic pollutants

  Presence of salt