Subshell Electronic Configuration

The (n−1)d¹⁰ns² configuration is typical for transition metals in their ground state, where 'n' represents the outermost shell.

Why is option (D) correct?

• Cu (Copper): The electronic configuration of Cu is [Ar] 3d¹⁰4s¹. It does not have the (n−1)d¹⁰ns² configuration.
• Zn (Zinc): The electronic configuration of Zn is [Ar] 3d¹⁰4s². It also does not have the (n−1)d¹⁰ns² configuration.

Why are the other options incorrect?

• Option (A): Cd (Cadmium) has the configuration [Kr] 4d¹⁰5s², which fits the (n−1)d¹⁰ns² pattern.
• Option (B): Hg (Mercury) has the configuration [Xe] 4f¹⁴5d¹⁰6s², which fits the (n−1)d¹⁰ns² pattern.
• Option (C): Cn (Copernicium) is a synthetic element and its configuration is not well established, but it is likely to have a configuration that fits the (n−1)d¹⁰ns² pattern.

Conclusion: The correct answer is (D) Cu, Zn because neither copper nor zinc has the (n−1)d¹⁰ns² configuration in their elementary state.