* The Reactivity Series: Metals are arranged in a series based on their reactivity. More reactive metals can displace less reactive metals from their compounds. Copper is lower in the reactivity series than iron.
* Displacement Reaction: In a displacement reaction, a more reactive metal will displace a less reactive metal from its salt solution. In this case, if a reaction were to occur, copper would have to displace iron from the FeSO4 solution.
* No Displacement: Since copper is less reactive than iron, it cannot displace iron from its salt, FeSO4. Therefore, no reaction occurs.
In summary, copper does not react with FeSO4 because copper is less reactive than iron, and cannot displace it from the solution.
