Write the electronic configuration of the following ions.

Options

A. `Mn^(2+)`
B. `Fe^(3+)`
C. `Ni^(2+)`
D. `Cr^(3+)`

Answer

To write the electronic configuration of the given ions, we will first determine the electronic configuration of the neutral atoms and then adjust for the charge of the ions by removing electrons from the appropriate orbitals. Here's the step-by-step solution for each ion:

### Step 1: Manganese Ion (Mn²⁺)
1. **Determine the atomic number of Manganese (Mn)**: Mn has an atomic number of 25.
2. **Write the electronic configuration of neutral Mn**:
- The electronic configuration is:
\[ \text{Mn: } [\text{Ar}] 4s^2 3d^5 \]
3. **Adjust for the +2 charge**:
- Remove 2 electrons from the 4s orbital (as electrons are removed from the outermost shell first).
- Resulting configuration for Mn²⁺:
\[ \text{Mn}^{2+}: [\text{Ar}] 3d^5 \]

### Step 2: Iron Ion (Fe³⁺)
1. **Determine the atomic number of Iron (Fe)**: Fe has an atomic number of 26.
2. **Write the electronic configuration of neutral Fe**:
- The electronic configuration is:
\[ \text{Fe: } [\text{Ar}] 4s^2 3d^6 \]
3. **Adjust for the +3 charge**:
- Remove 2 electrons from the 4s orbital and 1 electron from the 3d orbital.
- Resulting configuration for Fe³⁺:
\[ \text{Fe}^{3+}: [\text{Ar}] 3d^5 \]

### Step 3: Nickel Ion (Ni²⁺)
1. **Determine the atomic number of Nickel (Ni)**: Ni has an atomic number of 28.
2. **Write the electronic configuration of neutral Ni**:
- The electronic configuration is:
\[ \text{Ni: } [\text{Ar}] 4s^2 3d^8 \]
3. **Adjust for the +2 charge**:
- Remove 2 electrons from the 4s orbital.
- Resulting configuration for Ni²⁺:
\[ \text{Ni}^{2+}: [\text{Ar}] 3d^8 \]

### Step 4: Chromium Ion (Cr³⁺)
1. **Determine the atomic number of Chromium (Cr)**: Cr has an atomic number of 24.
2. **Write the electronic configuration of neutral Cr**:
- The electronic configuration is:
\[ \text{Cr: } [\text{Ar}] 4s^1 3d^5 \]
3. **Adjust for the +3 charge**:
- Remove 1 electron from the 4s orbital and 2 electrons from the 3d orbital.
- Resulting configuration for Cr³⁺:
\[ \text{Cr}^{3+}: [\text{Ar}] 3d^3 \]

### Summary of Electronic Configurations
- **Mn²⁺**: \([ \text{Ar} ] 3d^5\)
- **Fe³⁺**: \([ \text{Ar} ] 3d^5\)
- **Ni²⁺**: \([ \text{Ar} ] 3d^8\)
- **Cr³⁺**: \([ \text{Ar} ] 3d^3\)