How do you predict if a metal ION will react with a metal ATOM?
metals tend to have just one or two free electrons loosely bound. the S, P, and D orbitals aren't tight, and as such, the metals are most likely to lose the electron. the non-metal can emit as well, but given that it takes far less energy to remove a metal electron, the metal electron is likely to be the source. it's kind of like putting a piece of paper up against a piece of steel. sure, if you can punch through the steel, then you'll see your hole. but you will almost certainly punch through the paper before then.
