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

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

Copper atoms normally have 29 electrons. These 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 $Cu$$^+$$^2$ should have 27 electrons, which means that the shells are assigned like this: $K = 2, L = 8, M = 17$.

So when the $Cu$$^+$$^2$ ions react to $Fe$, why does it want to become $Cu$? Because $Cu$ doesn't have a complete electron shell at the end. Why doesn't it want to become $C$$^+, because then it would have a complete shell at the end (K=2, L=8, M=18). I know that when you take away electrons from Copper, it does it in a special way. I'm 15 years old and not english so I'm really not an expert or anything, I'm just wondering why Cu$$^+$$^2$ would want to become $Cu$ when it meets iron ($Fe$). Sincere thanks for any answers!