The electronic configuration of copper is `[Ar] 4s^(1) 3d^(10)` and not `[Ar] 4s^(2) 3d^(9)`. Justify.

Electronic configuration of copper is 3d^(10)4s^(1) instead of 3d^(9) 4s^(1) .Why?

(A) : The electronic configuration of Cr is [Ar]3d^(5) 4s^(1) but not [Ar]3d^(4) 4s^(2) (R) : Lowering energy with configuration [Ar]3d^(5)4s^(1) is more than that with configuration [A]3d^(4)4s^(2)

(A) : The electronic configuration of Cr is [Ar]3d^(5)4s^(1) but not [Ar]3d^(4)4s^(2) (R) : Lowering energy with configuration [Ar]3d^(5) 4s^(1) is more than that with configuration [Ar]3d^(4)4s^(2)

The electronic configuration of valence shell of Cu is 3d^(10)4s^(1) and not 3d^(9)4s^(2) . How is this configuration explained?

The electronic configuration of valence shell of Cu is 3d^(10)4s^(1) and not 3d^(9)4s^(2) . How is this configuration explained?

Account for the following: a. The expected electronic configuration of copper is '[Ar] 3d^9 4s^2' but actually it is '[Ar] 3 d^(10) 4 s^1' b. In building up of atoms, the filling of 4s orbitals occurs before '3 d' - orbitals.

Electronic configuration of M^(3+) is [Ar]3d^(10)4s^(2) , it belongs to