The stability of ferric ion is due to

Options

A. a. half-filled d-orbitals
B. b. half-filled f-orbitals
C. c. completely filled d-orbitals
D. d. completely filled f-orbitals

Answer

To determine the stability of the ferric ion (Fe³⁺), we need to analyze its electronic configuration and the factors that contribute to its stability.

### Step-by-Step Solution:

1. **Identify the Ferric Ion**:
- The ferric ion refers to iron in the +3 oxidation state, denoted as Fe³⁺.

2. **Determine the Electronic Configuration of Iron**:
- The atomic number of iron (Fe) is 26. The ground state electronic configuration of iron is:
\[ \text{Fe: } [\text{Ar}] 4s^2 3d^6 \]

3. **Calculate the Electronic Configuration of Fe³⁺**:
- When iron loses three electrons to form Fe³⁺, it loses both electrons from the 4s orbital and one electron from the 3d orbital. Thus, the electronic configuration becomes:
\[ \text{Fe}^{3+}: [\text{Ar}] 3d^5 \]

4. **Analyze the Stability of the Configuration**:
- The configuration 3d⁵ is significant because it is half-filled. Half-filled and fully filled subshells are known to confer extra stability due to symmetry and exchange energy.

5. **Conclusion**:
- The stability of the ferric ion (Fe³⁺) is due to its half-filled d-orbital configuration (3d⁵). This makes it more stable compared to other configurations.

### Final Answer:
The stability of the ferric ion is due to the half-filled d-orbital configuration.

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