Which of the following is the correct electronic configuration of (Z = 29)?

Question

Which of the following is the correct electronic configuration of  (Z = 29)?

Canvas Classes · Accepted Answer

Cu (Z=29) — anomalous configuration:

Expected:

Actual:

Reason: The completely filled  configuration is extra stable (exchange energy). One electron from 4s shifts to 3d to achieve this stability:

Similarly, Cr (Z=24) has  (half-filled  is extra stable).

Answer: Option (2) —

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