Highest electron affinity is shown by

Options

A. `F^(-)`
B. `Cl^(-)`
C. `NA^(+)`
D. `Li^(+)`

Answer

To determine which ion has the highest electron affinity among the options given (F-, Cl-, Na+, Li+), we will analyze each option step by step.

### Step 1: Understanding Electron Affinity
Electron affinity is the energy change that occurs when an electron is added to a neutral atom in the gas phase. A higher electron affinity means that the atom or ion more readily accepts an electron.

### Step 2: Analyzing the Options
- **F- (Fluoride Ion)**: This ion has gained an electron and is smaller in size compared to Cl-. When an additional electron is added to F-, the inter-electronic repulsion is significant due to the small size and high electron density. However, F- is already stable and can still accept an electron, but it will require more energy due to the repulsion.

- **Cl- (Chloride Ion)**: Similar to F-, Cl- has also gained an electron. However, it is larger in size than F-, which means the electron-electron repulsion is less significant. Therefore, Cl- can accept an additional electron more easily than F-.

- **Na+ (Sodium Ion)**: Na+ is a cation and has already lost an electron. It is in a stable form and does not have a tendency to gain an electron, making its electron affinity not applicable in this context.

- **Li+ (Lithium Ion)**: Like Na+, Li+ is also a cation and has lost an electron. It is in a stable state and will not gain an electron, thus having negligible electron affinity.

### Step 3: Comparing Electron Affinities
From the analysis:
- F- has a higher electron affinity than Cl- because, despite the higher repulsion when adding an electron to F-, it is still more stable than Cl-.
- Na+ and Li+ do not have significant electron affinities as they are already in a stable cationic state.

### Conclusion
The ion with the highest electron affinity among the given options is **F-**.

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