The actual electronic configuration of $\ce{Cu}$ ($Z = 29$) is:

Question

Accepted Answer

$1s^2\,2s^2\,2p^6\,3s^2\,3p^6\,3d^{10}\,4s^1$

Answer

$1s^2\,2s^2\,2p^6\,3s^2\,3p^6\,3d^9\,4s^2$

Answer

$1s^2\,2s^2\,2p^6\,3s^2\,3p^6\,4s^2\,3d^9$

Answer

$1s^2\,2s^2\,2p^6\,3s^2\,3p^6\,3d^7\,4s^2$

The actual electronic configuration of Cu\ce{Cu}Cu (Z=29Z = 29Z=29) is: