Which of the following will have highest bond energy ?

Options

A. `F_2`
B. `N_2`
C. `F_2^-`
D. `O_2^-`

Answer

To determine which of the given molecules has the highest bond energy, we will analyze the bond order of each molecule. Bond energy is directly related to bond order; the higher the bond order, the stronger the bond and the more energy is required to break it.

### Step-by-Step Solution:

1. **Identify the Molecules**: We need to analyze the following molecules: F2, N2, F2-, and O2-.

2. **Determine Bond Order**:
- **F2**:
- The bond order is calculated as the number of bonding electrons minus the number of anti-bonding electrons divided by 2.
- F2 has a bond order of 1 (single bond).

- **N2**:
- N2 has a triple bond between the two nitrogen atoms.
- The bond order is 3 (triple bond).

- **F2-**:
- F2- has a total of 19 electrons.
- The electronic configuration is:
- σ1s² σ*1s² σ2s² σ*2s² σ2p² (2 bonding from σ2p, 2 from π2p, and 1 from σ*2p).
- Total bonding electrons = 10, anti-bonding electrons = 9.
- Bond order = (10 - 9) / 2 = 0.5.

- **O2-**:
- O2- has a total of 17 electrons.
- The electronic configuration is:
- σ1s² σ*1s² σ2s² σ*2s² σ2p² (2 bonding from σ2p, 2 from π2p, and 1 from σ*2p).
- Total bonding electrons = 10, anti-bonding electrons = 7.
- Bond order = (10 - 7) / 2 = 1.5.

3. **Compare Bond Orders**:
- F2: Bond order = 1
- N2: Bond order = 3
- F2-: Bond order = 0.5
- O2-: Bond order = 1.5

4. **Conclusion**:
- The molecule with the highest bond order is N2 with a bond order of 3. Therefore, N2 will have the highest bond energy.

### Final Answer:
**N2 has the highest bond energy.**