1Swapping places
Iron is more reactive than copper, so it pushes copper out of copper sulfate. This is a displacement reaction.
displacementreactive
Lesson 11.4 notes
Displacement reactions
A more reactive metal pushes a less reactive one out of its compound.
2The atoms swap
Fe + CuSO₄ → FeSO₄ + Cu. Iron takes copper's place in the compound, and the copper is left on its own.
compound
3Testing the metals
Put each metal in solutions of the others. The metal that displaces the most others is the most reactive.
reactivity
4The reactivity series
The reactivity series lists metals from most to least reactive. A metal can displace any metal below it.
reactivity series
5Only one way
Copper is less reactive than magnesium, so copper in magnesium sulfate solution does nothing at all.
no reaction
6Thermite
Aluminium takes the oxygen from iron oxide. So much heat is given out that the iron made is molten. It is used to weld railway lines.
thermite
7Getting metals from ores
Carbon is more reactive than iron, so heating iron oxide with carbon takes the oxygen away and leaves iron.
orecarbon
Explore: Displacement lab
Put each metal into each solution, then work out the reactivity order.
Common mistake: Displacement only goes one way
Copper in magnesium sulfate solution does nothing. A less reactive metal can't push out a more reactive one: the more reactive metal always ends up in the compound.
Remember
- A more reactive metal displaces a less reactive metal from its compound.
- iron + copper sulfate → iron sulfate + copper. The nail turns brown and the blue colour fades.
- Reactivity: magnesium > zinc > iron > copper. Carbon can take the oxygen from iron oxide.
Going further at GCSE
GCSE: The reactivity series → GCSE: Displacement reactions → GCSE: Extracting metals →