1. Displacement reactions In a displacement reaction a more reactive element takes the place of a less reactive one in a compound

2. Aluminium + iron oxide → iron + aluminium oxide The aluminium displaces the iron because aluminium is more reactive than iron.

3. Aluminium + magnesium oxide → no reaction The aluminium CANNOT displace the magnesium because aluminium is less reactive than magnesium.

4. magnesium+ copper sulfate → magnesium sulfate + copper The magnesium displaces the copper because magnesium is more reactive than copper.