Question Detail
Question
Which elements exhibit anomalous electron configurations due to the closeness of the 3d and 4s orbital energies?
Correct Answer
Option C is the correct answer.
Detailed Explanation
Chromium and copper exhibit anomalous electron configurations due to the closeness of the 3d and 4s orbital energies. Chromium prefers [Ar] 4s¹ 3d⁵ rather than [Ar] 4s² 3d⁴, and copper prefers [Ar] 4s¹ 3d¹⁰ rather than [Ar] 4s² 3d⁹. These configurations provide extra stability from half-filled or fully filled d subshells.
Hint
Recall which elements are commonly cited as exceptions to the standard filling order.