Question

Which of the following atoms does the electron configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^2$ represent?

• A. An excited state $Ca$ atom
• B. A ground state $Ca$ atom
• C. An excited state $Sc$ atom
• D. An excited state $K$ atom

Answer 1

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

The given element has total $2+2+6+2+6+2=20$ electrons. Thus the element is $Ca$. However this is not ground state of $Ca$ as ground state configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$. Thus the given configuration is of excited state of $Ca$ atom.