Which of the following arrangements represents the correct order of electronic energy level?
-
A.
1s 2p 2s 3p 3s 3d 4s -
B.
1s 2s 2p 3s 3p 3d 4s -
C.
1s 2s 2p 3s 3p 4s 3d -
D.
1s 2s 3s 2p 3p 4s 3d
Which of the following arrangements represents the correct order of electronic energy level?