Which of the following represents the correct ground-state electron configuration for the Mn^{2+} ion?

• A. 1s^2 2s^2 2p^6 3s^2 3p^6 3d^4
• B. 1s^2 2s^2 2p^6 3s^2 3p^6 3d^3 4s^2
• C. 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6
• D. 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5

Answer: (D)

Verified step by step guidance

1. Identify the atomic number of manganese (Mn), which is 25, meaning a neutral Mn atom has 25 electrons.
2. Write the ground-state electron configuration for neutral Mn: \$1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5$.
3. Recognize that the Mn\(^{2+}\) ion has lost 2 electrons compared to the neutral atom, so it has 23 electrons.
4. Recall that when transition metals form cations, electrons are removed first from the outermost s orbital (4s) before the d orbitals.
5. Remove 2 electrons from the 4s orbital of the neutral Mn configuration, resulting in the Mn\(^{2+}\) configuration: \$1s^2 2s^2 2p^6 3s^2 3p^6 3d^5$.