[LolaGoesLala]

Why is there a 4 after Ammonia, in this complex ion, i mean how did they get that, [Cu (NH₃)₄]²⁺

[Arkcon]

That means there a 4 molecules of ammonia associated with the copper atom.  Chemical complexes aren't simple molecules, like NaCl is one sodium atom and one chloride atom "bound" to one another.  http://en.wikipedia.org/wiki/Coordination_complex  You want to start with the definition on that page, and maybe the history, and then see what you can find in your textbook or recent class notes.