Reactivity Series of Metals

• Reactivity Series of Metals

  • Potassium
  • Sodium
  • Calcium
  • Magnesium
  • Aluminium
  • Zinc
  • Iron
  • Copper
• Metal Reactivity 


  Metals that are higher reactivity series react faster and more vigorously. The reactivity of a metal depends on the tendency of the metal to lose outer shell electron and form a positive ion. The greater the tendency to lose outer shell electrons, the more reactive the metal.
• Reactivity of Potassium and Sodium

  • The reactivity increases down group 1
  • Potassium is more reactive than Sodium
  • Both sodium and potassium atoms lose one electron from their outer shell when they react to form a positive ion
  • Na->Na+ + e-
  • K->K+ + e-
  • Outer shell electron from potassium ion is further from the nucleus than for the lost electron in sodium and the outer electron is shielded from the attraction of the positively charged nucleus by more inner electrons
• Group 2

  • elements are less reactive than group 1
  • Magnesium is less reactive than sodium
  • Magnesium loses 2 electrons from the outer shell to form a positive ion
  • Mg->Mg2+ + 2e-
  • Magnesium atom is smaller than sodium atom and so the outer electrons lost from a Mg atom are closer to the positive nucleus
  • Two electrons are lost from a Mg atom whereas only one is lost from a Na atom
• Transition Metals

  • smaller atoms than atoms of group 1 and 2 in the same period
  • outer electrons are closer to the nucleus making them less reactive
• Potassium reaction with air

  • burns with lilac flame
  • forms a white solid
  • when freshly cut, shiny surface tarnishes quickly
  • 4K+O2->2K2O
• Sodium reaction with Air

  • Burns with yellow/orange flame
  • forms a white solid
  • when freshly cut, shiny surface tarnishes quickly
  • 4Na+O2->2Na2O
• Calcium reaction with air

  • burns with brick red flame
  • forms a white solid
  • reacts slowly, forming an oxide layer on surface
  • 2Ca+O2->2CaO
• Magnesium reaction with air

  • burns with bright, white light
  • forms a white solid
  • reacts slowly, forming an oxide layer on surface
  • 2Mg+O2->2MgO
• Iron reaction with air

  • Burns with orange sparks when in form of filings
  • forms a black solid
  • react slowly, forming an oxide layer on surface
  • 3Fe+2O2->Fe3O4
  • Fe3O4 is a mixed oxide
• Copper reaction with air

  • does not burn
  • forms a black solid
  • reacts slowly, forming an oxide layer on the surface
  • 2Cu + O2 -> 2CuO
• Reactivity of metals

  • sodium, potassium and calcium are only heated in the air under very careful supervision and strict safety procedures. The reactions can be extremely dangerous
  • all other metals listed can be heated in air in a crucible
  • usually the powder form of the metal is heated.
  • crucible lid is lifted occasionally during heating to allow more air to get in to the crucible
• Reactions of metal with air

  when metals react with air, they gain mass because they form an oxide
• All the metals react faster and more vigorously in pure oxygen compared with air
• Equipment for reactions with air

  • crucible
  • crucible lid
  • pipe clay triangle
  • tripod
  • heatproof mat
  • bunsen burner
• Reactions of metals with water 


  when sodium and potassium are reacted with water, a small piece of the metal is placed in a trough half full of water. This reaction is carried out behind a safety screen. Tongs or tweezers are used to handle the metal
• Potassium reaction with water

  • floats on surface
  • moves around on surface
  • burns with a lilac flame
  • fizzes/gas given off
  • heat is released
  • small explosion/crackles
  • eventually disappears
  • forms a colourless solution
  • 2K+2H2O->2KOH+H2
• Sodium reacting with water

  • floats on surface
  • moves about surface
  • melts and forms a silvery ball
  • fizzes, giving off a gas
  • heat is released
  • eventually disappears
  • forms a colourless solution
  • 2Na+2H2O->2NaOH+H2
• Potassium and sodium are stored under oil to prevent it reacting with oxygen and moisture in the air
• Calcium reaction with water

  • fizzes, giving off gas
  • sinks then rises
  • heat is released
  • eventually disappears
  • forms a colourless solution
  • Ca + 2H2O -> Ca(OH)2 + H2
• Magnesium reaction with water

  • very slow reaction
  • few bubbles of gas given off
  • Mg+ 2H2O -> Mg(OH)2 + H2
• Reaction of metals with water-Mg+Ca 


  To react Mg or Ca with water, the metal is put in water in a beaker and an inverted filter funnel is placed over the metal. A boiling tube filled with water is used to collect the hydrogen produced
• Equipment used to collect gas

  • boiling tube
  • beaker
  • filter funnel
  • water

  When magnesium reacts only few gas bubbles are produced over several days
• Magnesium reacting with steam

  • the heated ribbon burns with a bright, white light
  • forms a white solid
  • heat is released
  • Mg+H2O->MgO+H2
• Aluminium reacting with steam

  • no reaction in foil form unless protective layer of aluminium oxide is removed
  • powdered form burns to form a white solid
  • heat is released
  • 2Al + 3H2O -> Al2O3 + 3H2
• Zinc reacting with steam

  • Powdered form glows to form a yellow solid which changes to white on cooling
  • heat is released
  • Zn+H2O->ZnO+H2
• Iron reacting with steam

  • powdered form glows at red heat, forming a black solid
  • 3Fe+ 4H2O -> Fe3O4+ 4H2
• Steam reactions apparatus

  • The apparatus is connected to a delivery tube and the gas produced is collected over water, using a beehive shelf and a gas jar. The gas produced is hydrogen
  • damp mineral wool
  • test tube and delivery tube
  • trough and beehive shelf
  • gas jar
• Damp mineral wool and heating

  Damp mineral wool is heated to generate steam. When the heating stops, there is a risk of suck-back occurring. (the water in the trough being drawn back into the hot boiling tube) This can be prevented by removing the apparatus from the water in the trough or taking the bung out of boiling tube
• Aluminium

  The reactivity of aluminium is often hidden because aluminium metal forms a protective oxide layer on its surface

  • a piece of aluminium foil doesn’t react with air, water or steam because of the protective oxide layer
  • powdered aluminium shows true reactivity
  • aluminium is reasonably reactive, but the protective aluminium oxide layer means it can be used for saucepans without reacting with food
• Displacement reactions

  These involve a transfer of electrons. This is a reaction in which a more reactive metal takes the place of a less reactive metal in a compound
• Types of displacement reactions

  • a solid metal reacting with a solution of a metal ion
  • a solid metal reacting with a solid metal oxide
• Solutions

  main observations to look out for are:

  • colour change-copper(II)sulfate solution is used as it gives a definitive colour change
  • release of heat- displacement reactions are exothermic. The bigger the difference in reactivity of the metals, the more heat will be released
• Solutions 


  Main observations to look out for:

  • colour change- copper(11) sulfate solution is used as it gives a definite colour change
  • release of heat-displacement reactions are exothermic. The bigger the difference in reactivity the more heat released
  • appearance of the solid metals that are displaced from solution
• Displacements Reactions to determine reactivity

  • a set of reactions between metals and their metal salt solutions are carried out
  • the metals are placed in a solution of metal salt- usually sulfate as most are soluble or nitrates as all are soluble
• Displacement Reaction with sulfate solutions

  • Magnesium displaces copper, iron and zinc-most reactive
  • Zinc displaces copper and iron but not magnesium- therefore 2nd most reactive
  • Iron displaces copper but nothing else-3rd most reactive
  • Copper doesn't replace any- least reactive
• Solids 


  When solid metal compounds (oxides) are heated with a solid, a displacement and redox reaction occurs.

  • reactions are carried out in a crucible with same apparatus as heating a metal in air
  • reactions are carried out with both metal oxide and oxide in powder form to increase contact between solids
  • exothermic
  • exothermic reaction depends on how far apart the metals are in the reactivity series. The further apart, the faster and more exothermic the reaction
  • If a mixture of Mg powder and copper(11)oxide is heated, crucible explodes as powdered metals are very flammable
• Extraction of metals from their ores 


  Most metal ores are oxides of the metal and some are converted to oxides before the metal is extracted
• Ore 


  an ore is a rock which contains enough of a metal or metal compound to make extraction economically worthwhile
• Extraction from ore process

  • the lowest reactivity metals are found uncombined in nature (native)
  • metals that are high in the reactivity series are extracted by electrolysis
  • metals that are low in reactivity series are extracted by reduction with carbon or carbon monoxide
  • For metals like Al and above in the reactivity series, electrolysis must be used for extraction
  • all methods require reduction which is a gain of electrons/loss of oxygen