F4 Chem metals HELP!!!!!

A more reactive metal can displace a less reactive metal for thesolution of its salt.

all of magnesium, zinc and iron are more reactive than copper. Therefore, all of these three metals candisplace copper for the solution of copper(II) sulphate. The ionic equations are shown below :
Mg(s) + Cu²⁺(aq) → Mg²⁺(aq) + Cu(s)
Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s)
Fe(s) + Cu²⁺(aq) → Fe²⁺(aq) + Cu(s)

The Mg²⁺, Zn²⁺ and Fe²⁺ ions formed are colouless, colourless and pale green respectively. As copper(II) ions are converted to coppermetal, the blue colour of copper(II) ions fades gradually.

2012-11-21 23:31:22 補充：
Note that there is no such substance SO4 in the world.
世上沒有 SO4 的存在。

In the reaction mixture, SO4²⁻ ions are called spectator ions or dummy ions, as they are NOT involved in any reaction.
在反應混合物中，因 SO4²⁻ 離子並不涉及任何反應，故稱為旁觀離子。