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THE  ACTIVITY SERIES    (Reactivity series)

A list of elements (usually metals) arranged in an order to show how easily they form compounds.

Any element in the list will always be able to reduce (take oxygen away from) the oxide of an element lower down in the list.

Some elements arranged in order of chemical activity. The rate of chemical reactivity increases as you go up the list

Calcium

Magnesium

Zinc

Iron

Copper

Lead

Gold

 

 More reactive metals

 

 

 

Less reactive metals

Metals nearer the top of the list will

  • Burn more rapidly in air.

  • React faster with water.

  • React faster with dilute acids.
  • Be able to replace a lower metal from one of its compounds
  • More likely to be found in a compound.

 

example 1. heating magnesium powder with copper oxide

Result: A violent exothermic reaction. The copper oxide was reduced by the magnesium to leave magnesium oxide and copper.
(The heat of the reaction makes most of the copper turn back to copper oxide)

Word Equation: Magnesium + copper oxide  ---->  magnesium oxide + copper

The magnesium oxide has been reduced by the copper
The magnesium has been oxidised by the copper oxide

The reaction above shows us that magnesium is MORE reactive than copper.

example 2. Heating zinc powder with magnesium oxide

result: NOTHING will happen. The zinc cannot reduce the magnesium oxide. This shows us that zinc is LESS reactive then magnesium.

example 3: Iron will displace copper from a solution of copper sulphate in water.

The copper sulphate loses its colour and the iron acquires a coating of pink copper.

Word equation: Copper sulphate + Iron ----> iron sulphate + copper

example 4 If Some magnesium ribbon is plunged into a gas jar containing carbon dioxide gas the magnesium will reduce the acrbon dioxide to leave black specks of carbon and magnesium oxide

Word equation: Magnesium + carbon dioxide ---> carbon dioxide + carbon

example 4: Calcium metal will reduce water* to form hydrogen gas and leave a white residue of calcium oxide. This reaction shows us that calcium is more reactive than hydrogen.

(* remember that water is an oxide of hydrogen)

Word equation: Calcium + water --->  calcium oxide + hydrogen

New Vocabulary:
Reduce: To take oxygen away from a compound. Eg if copper oxide is reduced by zinc it will turn into copper.

Exothermic: A reaction which gives out heat.
 Eg magnesium burning is an exothermic reaction