Displacement Reactions and the Reactivity Series — AQA GCSE Chemistry
The reactivity series ranks metals by how readily they react, and explains displacement reactions and metal extraction.
The reactivity series
Metals can be arranged in order of reactivity by how vigorously they react with water and acids:
potassium > sodium > lithium > calcium > magnesium > (carbon) > zinc > iron > (hydrogen) > copper > silver > gold
Carbon and hydrogen (non-metals) are included for comparison. Metals react by losing electrons to form positive ions (oxidation) — the more reactive the metal, the more easily it does this.
Displacement reactions
A more reactive metal displaces a less reactive metal from a compound (usually a solution of its salt).
Example
iron + copper sulfate → iron sulfate + copper Iron is more reactive, so it displaces the copper. This is a redox reaction: iron is oxidised (loses electrons) and copper ions are reduced (gain electrons).
Extraction of metals
- Metals less reactive than carbon can be extracted by reduction with carbon (e.g. iron from iron oxide).
- Metals more reactive than carbon (e.g. aluminium) must be extracted by electrolysis.
- Very unreactive metals (gold) are found native (as the metal).
Exam tips
- Learn the reactivity series order, including carbon and hydrogen.
- A more reactive metal displaces a less reactive one from its salt.
- Displacement is a redox reaction (explain electron transfer).
- Extraction method depends on the metal's position relative to carbon.