# Why should the redox reaction happen between the copper ions and iron atoms?

I know that when $$\ce{Cu^{2+}}$$ ions react to $$\ce{Fe}$$ atoms, it becomes $$\ce{Cu}$$ + $$\ce{Fe^{2+}}$$. My question is, why?

Copper atoms normally have 29 electrons. This means that in the K-shell there are 2 electrons, in $$L = 8$$ electrons, in $$M = 18$$ electrons and in $$N = 1$$ electron. (Yes I know that there is a system with s and other letters, but I haven't been taught in that way at my school). Therefore $$\ce{Cu^{2+}}$$ should have 27 electrons, which means that the shells are assigned like this: $$K = 2, L = 8, M = 17$$.

So when the $$\ce{Cu^{2+}}$$ ions react with $$\ce{Fe}$$, why does it want to become $$\ce{Cu}$$? Because $$\ce{Cu}$$ doesn't have a complete electron shell at the end. Why doesn't it want to become $$\ce{Cu+}$$, because then it would have a complete shell at the end ($$K=2, L=8, M=18$$).

I know that when you take away electrons from copper, it does it in a special way. I'm 15 years old and not english so I'm really not an expert or anything, I'm just wondering why $$\ce{Cu^{2+}}$$ would want to become $$\ce{Cu}$$ when it meets iron ($$\ce{Fe}$$).