Question

The element with electronic configuration of its atom $1s^2,2s^2,2p^6,3s^2,3p^6,3d^{10},4s^1$ is:

• A. $fe$
• B. $Co$
• C. $Ni$
• D. $Cu$

Answer 1

The correct option is D $Cu$

The element with electronic configuration of its atom $1s^2,2s^2,2p^6,3s^2,3p^6,3d^{10},4s^1$ is $Cu$

Actually its configarartion is $1s^2,2s^2,2p^6,3s^2,3p^6,3d^9,4s^2$ but for stability i.e completely filled d orbital gives more stability that is the reason why it attains above configaration.

Hence option D is correct.