[单选题]
Which of the following subshells contains the highest energy?
A. 2s
B. 2p
C. 2d
D. 3d
参考答案: D
本题详细解析: According to Aufbau’s principle, the arrangement of subshell in increasing energy is 1s 2s 2p 3s 3p 4s 3d 4p. Therefore, Choices A and B are both incorrect. Choice C is incorrect because 2d does not exist.
