You can work out a reactivity series for many substances by carrying out displacement reactions. The table below shows the results of reacting different metals with different salt solutions.
|Magnesium sulfate solution||Copper(II) sulfate solution||Iron(II) sulfate solution||Number of reactions|
|Magnesium||Not done||Brown coating||Black coating||2|
|Copper||No visible reaction||Not done||No visible reaction||0|
|Iron||Brown coating||No visible reaction||Not done||1|
Magnesium is the most reactive metal from these three as it undergoes two reactions, iron is next and copper is the least reactive.
Here is the balanced ionic equation for the reaction between magnesium and copper(II) sulfate. The equation below shows the ions present on both sides of the equation:
Mg(s) + Cu2+(aq) + SO42-(aq) → Mg2+(aq) + SO42-(aq) + Cu(s)
Sulfate ions, SO42- , appear on both sides of the equation because they do not take part in the reaction. The ionic equation for the reaction is written without sulfate ions:
Mg(s) + Cu2+(aq) → Mg2+(aq) + Cu(s)