consider-the-following-illustration-of-the-periodic-table-identify-which-among-t

Question

Consider the following illustration of the periodic table. Identify which among the highlighted elements has an anomalous ground-state electron configuration. Justify your answer.

Periodic table highlighting elements A, B, and C for electron configuration anomalies.

Accepted Answer

B; The expected electron configuration of Ag is [Kr]5s²4d⁹ but the d orbitals prefer to have fully-filled orbitals so the actual electron configuration is [Kr]5s¹4d¹⁰.

Answer

A; The expected electron configuration of Cl is [Ne]3s²3p⁵ but the p orbitals prefer to have fully-filled orbitals so the actual electron configuration is [Ne]3s¹3p⁶.

Answer

C; The expected electron configuration of Cs is [Xe]6s¹ but the s orbitals prefer to have half-filled orbitals so the actual electron configuration is [Xe]6s².