Draw the molecular orbital diagram for F2-

Draw the molecular orbital diagram for F2-

The Correct Answer and Explanation is:

Molecular Orbital Diagram for F₂⁻

Steps to draw the molecular orbital diagram:

1. Electron Configuration of Fluorine Atom:
   Fluorine has an atomic number of 9, so the electron configuration is: 1s2 2s2 2p51s^2 \ 2s^2 \ 2p^51s2 2s2 2p5 When two fluorine atoms come together to form the F₂ molecule, they each contribute 9 electrons, giving a total of 18 electrons in the bonding molecular orbitals.
2. Molecular Orbitals for F₂⁻:
   The negative charge (F₂⁻) adds one more electron, increasing the total electron count to 19. This electron will be placed in one of the molecular orbitals.
3. Molecular Orbitals Energy Ordering:
   The molecular orbitals for diatomic molecules like F₂ are filled in the following order based on the energy level:
   • σ(1s)
   • σ*(1s)
   • σ(2s)
   • σ*(2s)
   • σ(2pz)
   • π(2px) = π(2py)
   • π*(2px) = π*(2py)
   • σ*(2pz)
4. Filling the Molecular Orbitals:
   The electrons are placed in the molecular orbitals, starting with the lowest energy levels:
   • σ(1s) and σ*(1s) each hold 2 electrons (total of 4).
   • σ(2s) and σ*(2s) each hold 2 electrons (total of 4).
   • σ(2pz) holds 2 electrons (total of 2).
   • π(2px) and π(2py) each hold 2 electrons (total of 4).
   • π*(2px) and π*(2py) each hold 2 electrons (total of 4).
   • σ*(2pz) holds 1 electron due to the negative charge (1 additional electron).
5. Bond Order:
   Bond order is calculated as: Bond order=12(Number of bonding electrons−Number of antibonding electrons)\text{Bond order} = \frac{1}{2} (\text{Number of bonding electrons} – \text{Number of antibonding electrons})Bond order=21​(Number of bonding electrons−Number of antibonding electrons) In F₂⁻:
   • Bonding electrons = 10 (σ(1s) + σ(2s) + σ(2pz) + π(2px) + π(2py))
   • Antibonding electrons = 9 (σ*(1s) + σ*(2s) + π*(2px) + π*(2py) + σ*(2pz))
   Therefore, the bond order is: Bond order=12(10−9)=12\text{Bond order} = \frac{1}{2} (10 – 9) = \frac{1}{2}Bond order=21​(10−9)=21​ So, the bond order for F₂⁻ is 1/2, indicating a weaker bond than in the neutral F₂ molecule.

In summary, F₂⁻ has a bond order of 1/2, and its molecular orbital diagram shows the placement of 19 electrons in bonding and antibonding orbitals. The additional electron in the antibonding σ*(2pz) orbital reduces the bond strength