# In a copper wire, how many electrons does each atom give away?

As an ion, copper can give off 1, 2, 3 or 4 electrons. But it has 1 s electron in the last shell and 10 d electrons. So as a metal, how many of those are delocalised and free to move around, and how many are staying with the atom?

• This question is better suited for Chemistry SE, really, but I think that all the electrons in the outermost shell ($n=4$) are free to move. – Anurag B. Jun 7 '18 at 14:18
• Roughly 1 electron per atom. If I could find a good ref proving that I'd post an answer, but the sites I've seen so far just state it without proof. – PM 2Ring Jun 7 '18 at 14:38