Which is the correct order of ionization energies?

Options

A. `F^(-) gt F gt Cl^(-) gt Cl`
B. `F gt Cl gt Cl^(-) gt F^(-)`
C. `F^(-) gt Cl^(-) gt Cl gt F`
D. `F^(-) gt Cl^(-) gt F gt Cl`

Explanation

To determine the correct order of ionization energies among the given species, we need to analyze the electronic configurations and the factors affecting ionization energy.

### Step-by-Step Solution:

1. **Understanding Ionization Energy**:
- Ionization energy is the energy required to remove an electron from an atom or ion. It generally increases across a period (left to right) and decreases down a group (top to bottom) in the periodic table.

2. **Identify the Species**:
- The species mentioned are:
- Chlorine (Cl): 1s² 2s² 2p⁶ 3s² 3p⁵
- Chloride ion (Cl⁻): 1s² 2s² 2p⁶ 3s² 3p⁶
- Fluorine (F): 1s² 2s² 2p⁵
- Fluoride ion (F⁻): 1s² 2s² 2p⁶

3. **Analyze the Electronic Configurations**:
- **Fluorine (F)** has 7 electrons in its outer shell (2s² 2p⁵) and is more electronegative than chlorine, meaning it has a stronger attraction to its electrons.
- **Chlorine (Cl)** has 7 electrons in its outer shell (3s² 3p⁵) but is in a higher energy level (n=3), which means it is larger and has a weaker hold on its outer electrons compared to fluorine.
- **Chloride ion (Cl⁻)** has gained an electron to achieve a full outer shell (3s² 3p⁶), resulting in a larger size and lower ionization energy than neutral chlorine.
- **Fluoride ion (F⁻)** also has a full outer shell (2s² 2p⁶) but is smaller than chloride ion, thus having a higher ionization energy than Cl⁻.

4. **Comparing Ionization Energies**:
- The order of ionization energies can be deduced as follows:
- F⁻ has the highest ionization energy because it is smaller and has a full outer shell.
- Cl⁻ comes next, as it is larger than F⁻ but still has a full outer shell.
- Cl has a lower ionization energy than Cl⁻ due to its larger size and less effective nuclear charge.
- F has the lowest ionization energy because it is neutral and has a stronger hold on its electrons than Cl.

5. **Final Order**:
- Therefore, the correct order of ionization energies is:
- F⁻ > Cl⁻ > Cl > F

### Conclusion:
The correct answer is that the order of ionization energies is F⁻ > Cl⁻ > Cl > F.