10. Periodic Properties of the Elements
The Electron Configurations: Exceptions
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1PRACTICE PROBLEM
Consider the following illustration of the periodic table. Identify which among the highlighted elements has an anomalous ground-state electron configuration. Justify your answer.
Consider the following illustration of the periodic table. Identify which among the highlighted elements has an anomalous ground-state electron configuration. Justify your answer.
ANSWERS OPTIONS
A
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.
B
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.
C
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.