The pair of ions having same electronic configuration is__________.

Options

A. `Cr^(3+),Fe^(3+)`
B. `Fe^(3+),Mn^(2+)`
C. `Fe^(3+),Co^(3+)`
D. `Sc^(3+),Cr^(3+)`

Explanation

To solve the question "The pair of ions having same electronic configuration is__________," we will analyze the electronic configurations of the given ions step by step.

### Step 1: Identify the ions and their atomic numbers
We have the following ions to consider:
1. Chromium ion (Cr³⁺)
2. Iron ion (Fe³⁺)
3. Manganese ion (Mn²⁺)
4. Cobalt ion (Co³⁺)
5. Scandium ion (Sc³⁺)

### Step 2: Determine the electronic configurations of the neutral atoms
- **Chromium (Cr)**: Atomic number = 24
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹

- **Iron (Fe)**: Atomic number = 26
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ 4s²

- **Manganese (Mn)**: Atomic number = 25
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s²

- **Cobalt (Co)**: Atomic number = 27
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s²

- **Scandium (Sc)**: Atomic number = 21
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹ 4s²

### Step 3: Determine the electronic configurations of the ions
1. **Chromium ion (Cr³⁺)**:
- Loses 3 electrons: 3d⁵ 4s¹ → 3d³

2. **Iron ion (Fe³⁺)**:
- Loses 3 electrons: 3d⁶ 4s² → 3d⁵

3. **Manganese ion (Mn²⁺)**:
- Loses 2 electrons: 3d⁵ 4s² → 3d⁵

4. **Cobalt ion (Co³⁺)**:
- Loses 3 electrons: 3d⁷ 4s² → 3d⁶

5. **Scandium ion (Sc³⁺)**:
- Loses 3 electrons: 3d¹ 4s² → 3d⁰ (or 3p⁶)

### Step 4: Compare the electronic configurations
Now we compare the electronic configurations of the ions:
- Cr³⁺: 3d³
- Fe³⁺: 3d⁵
- Mn²⁺: 3d⁵
- Co³⁺: 3d⁶
- Sc³⁺: 3d⁰

From the comparison:
- **Fe³⁺ and Mn²⁺ both have the same electronic configuration of 3d⁵.**

### Conclusion
The pair of ions having the same electronic configuration is **Fe³⁺ and Mn²⁺**.

### Final Answer
The correct option is: **Fe³⁺ and Mn²⁺.**

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