[msandra]

Reaction 1: Zn (s) + CuSO4 (aq) --> Cu (s) + ZnSO4 (aq)
Reaction 2: ZnSO4 (aq) + Cu (s) -->  no reaction

Zinc is more reactive.  In reaction 1, zinc replaced copper (II) ion to form a new compound with sulfate whereas in reaction 2, copper can not replace zinc to form new compound with sulfate. As a result, zinc is more reactive than copper.

Did I explain correctly? Any keys words I should use? Please help. Thanks

[Mitch]

Reactive is not descriptive enough. You have to describe the reactivity. Zn is more reactive to single replacement with sulfate. than Cu is.

[msandra]

thanks i will add:

Zinc has a higher reactivity than copper.