Write the electron configuration and electron orbital diagram for the following element: 
Mn (Z = 25) 

• A. 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵
• B. 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4d⁵
• C. 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴
• D. 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵

Answer: (D)

Verified step by step guidance

1. Identify the atomic number of manganese (Mn), which is 25. This means Mn has 25 electrons.
2. Write the electron configuration by filling the orbitals in order of increasing energy: 1s, 2s, 2p, 3s, 3p, 4s, and then 3d.
3. Distribute the 25 electrons among these orbitals following the Aufbau principle, Pauli exclusion principle, and Hund's rule.
4. The correct electron configuration for Mn is: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5.
5. Draw the electron orbital diagram: fill the 1s, 2s, 2p, 3s, 3p, and 4s orbitals completely, then place 5 electrons in the 3d orbitals, ensuring each 3d orbital gets one electron before any pairing occurs.