To draw the Molecular Orbital (MO) diagram for F₂ (fluorine molecule), we start by considering the atomic orbitals of the two fluorine atoms. Each fluorine atom has the electron configuration of 1s² 2s² 2p⁵, meaning each contributes its atomic orbitals for bonding.
1. **Identify Atomic Orbitals:** Each fluorine atom contributes:
– 2 electrons from the 1s orbital
– 2 electrons from the 2s orbital
– 5 electrons from the 2p orbitals
2. **Molecular Orbitals Formation:** In F₂, the 1s orbitals combine to form a lower energy bonding (σ1s) and a higher energy antibonding orbital (σ*1s). Similarly, the 2s orbitals also combine to form σ2s and σ*2s. The 2p orbitals form three molecular orbitals:
- Bonding orbitals: σ2p and π2p
- Antibonding orbitals: σ*2p and π*2p
3. **Filling Electrons in the MO Diagram:** The total number of valence electrons in F₂ is 14 (7 from each atom). These are filled into the molecular orbitals according to the Aufbau principle, Pauli Exclusion principle, and Hund’s rule.
4. **Electron Configuration for F₂:** The molecular orbital filling for F₂ becomes:
- σ1s²
- σ*1s²
- σ2s²
- σ*2s²
- σ2p² (2 electrons)
- π2p⁵ (4 electrons in π2p, with two electrons spread in the degenerate orbitals)
- π*2p² (2 electrons)
5. **Final MO Diagram:** The final MO diagram for F₂ looks like this:
– σ1s (2) – σ*1s (2)
– σ2s (2) – σ*2s (2)
– σ2p (2) – π2p (4)
– π*2p (0) – σ*2p (0)
This arrangement shows that F₂ has a bond order of 1, indicating a single bond between the two fluorine atoms, and the presence of unpaired electrons in the π2p orbitals suggests that F₂ is diamagnetic.