Chemistry - Atomic Structure Question with Solution | TestHub

The electronic configuration of Cu (Z=29) is $[Ar]3d^{10}4s^1$. The last electron enters the 3d subshell.

For the 3d subshell:

$n=3$ (principal quantum number)

$l=2$ (azimuthal quantum number for d-subshell)

$m_l$ can range from $-2,-1,0,+1,+2$.

Since the 3d subshell is completely filled ($3d^{10}$), the last electron will have $m_l=-2$ (following Hund's rule and filling order) and $m_s=-1/2$.

Thus, the quantum numbers are $(3,2,-2,-1/2)$.