Why is the element copper unreactive?
Copper, along with the other members of group 11A (gold and silver included) are unreactive metals because of their electron configuration. The s subshell promotes one of its electrons to the 3d subshell, giving it a filled 3 subshell and only one electron in its outer 4s subshell. Therefore, there is no electron-electron repulsion in the outer subshell, making all electrons rather stable in comparison to all other metals.
