Question

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^2$
The above electronic configuration is represented for which atoms among the following?

• A. An excited state $Ca$ atom
• B. A ground state $Ca$ atom
• C. An excited state $Sc$ atom
• D. An excited state $K$ atom
• E. None of the above

Answer 1

The correct option is A An excited state $Ca$ atom

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^2$

20 electrons are found in $Ca$ atom.

This is not the electronic configuration for $Ca$, but it is excited state of the $Ca$ where the 4s electrons have jumped to higher energy level (3d).

Hence, the correct option is A.