`Fe^(3+)` compounds are more stable than `Fe^(2+)` compounds because

Options

A. `Fe^(3+)` has smaller size than `Fe^(2+)`
B. `Fe^(3+)` has `3d^5` configuration (half-filled)
C. `Fe^(3+)` has higher oxidation state
D. `Fe^(3+)` is paramagnertic in nature.

Explanation

To understand why \( \text{Fe}^{3+} \) compounds are more stable than \( \text{Fe}^{2+} \) compounds, we can analyze the electronic configurations and the stability associated with them.

### Step-by-Step Solution:

1. **Identify the Electronic Configuration of Iron (Fe)**:
- Iron has an atomic number of 26. Its electronic configuration is:
\[ \text{Fe}: [\text{Ar}] \, 3d^6 \, 4s^2 \]

2. **Determine the Electronic Configuration of \( \text{Fe}^{2+} \)**:
- When iron loses two electrons to form \( \text{Fe}^{2+} \), the electrons are removed first from the 4s orbital. Thus, the electronic configuration becomes:
\[ \text{Fe}^{2+}: [\text{Ar}] \, 3d^6 \, 4s^0 \]

3. **Determine the Electronic Configuration of \( \text{Fe}^{3+} \)**:
- When iron loses a third electron to form \( \text{Fe}^{3+} \), it loses one more electron from the 3d orbital. Therefore, the electronic configuration is:
\[ \text{Fe}^{3+}: [\text{Ar}] \, 3d^5 \, 4s^0 \]

4. **Analyze the Stability of the Configurations**:
- The \( 3d^5 \) configuration of \( \text{Fe}^{3+} \) is a half-filled configuration. Half-filled and fully filled subshells are generally more stable due to symmetry and exchange energy.

5. **Conclusion**:
- Since \( \text{Fe}^{3+} \) has a half-filled \( 3d^5 \) configuration, it is more stable than \( \text{Fe}^{2+} \), which has a \( 3d^6 \) configuration. Thus, the stability of \( \text{Fe}^{3+} \) compounds is greater than that of \( \text{Fe}^{2+} \) compounds.

### Final Answer:
\( \text{Fe}^{3+} \) compounds are more stable than \( \text{Fe}^{2+} \) compounds because \( \text{Fe}^{3+} \) has a half-filled \( 3d^5 \) configuration, which is more stable than the \( 3d^6 \) configuration of \( \text{Fe}^{2+} \).

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