Give the electron configuration for a neutral atom of manganese (Mn) using an orbital diagram (the kind with lines or boxes for orbitals and arrows to show the electrons).
The correct answer and explanation is :
Electron Configuration of a Neutral Manganese (Mn) Atom:
The atomic number of manganese (Mn) is 25, meaning it has 25 electrons in a neutral atom. The electron configuration is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵
Orbital Diagram Representation:
1s ↑↓
2s ↑↓
2p ↑↓ ↑↓ ↑↓
3s ↑↓
3p ↑↓ ↑↓ ↑↓
4s ↑↓
3d ↑ ↑ ↑ ↑ ↑ Explanation:
- Aufbau Principle: Electrons fill orbitals starting from the lowest energy level to the highest.
- Pauli Exclusion Principle: Each orbital can hold a maximum of two electrons with opposite spins.
- Hund’s Rule: When filling degenerate orbitals (orbitals of the same energy level), electrons fill singly first before pairing up.
- 1s (2 electrons): The first energy level contains one orbital (1s), which holds two electrons.
- 2s (2 electrons): The second energy level starts with the 2s orbital, which also holds two electrons.
- 2p (6 electrons): The 2p orbitals (three orbitals) can hold six electrons in total.
- 3s (2 electrons): The third energy level starts with the 3s orbital, holding two electrons.
- 3p (6 electrons): The three 3p orbitals hold six electrons.
- 4s (2 electrons): The 4s orbital is filled before the 3d orbitals because it is lower in energy.
- 3d (5 electrons): The five 3d orbitals are filled according to Hund’s Rule, meaning each gets one electron before any pairing occurs.
This configuration shows why manganese has a half-filled 3d⁵ subshell, making it relatively stable due to exchange energy and symmetry.