Question

Which of the following electron configuration would be those atoms in ground state? In excited states? Which are just plain wrong?
A. 1s2 2p2
B. 1s2 2s2 2p5 4f1
C. 1s2 2s2 2p6 3s1 3d1

Answer 1

C. $1s^22s^22p^63s^13d$ is in ground state

A. $1s^22p^2$ is in excited state

B. $1s^22s^22p^54f^1$ is plain wrong