Question

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?

Answer 1

In metallic copper, the one 4s electron becomes delocalised and acts as a conduction electron, contributing to copper's excellent electrical conductivity, while the d electrons are not as freely mobile.

Step-by-step explanation:

As a transition metal, copper has one s electron in the outermost shell and ten d electrons in the next-to-outermost shell. In metallic copper, the 4s electron is delocalised and free to move around, acting as a conduction electron. This is because the 4s orbital is higher in energy and the electron in this orbital is more loosely bound, making it easier for this electron to move to a neighboring atom.

Therefore, in a copper wire, each copper atom contributes one free electron to the electron 'sea', and these free electrons are responsible for the excellent electrical conductivity of copper. The rest of the electrons, mainly the d electrons, remain closer to the nucleus and are not as freely mobile.