Which of the following contains the maximum number of unpaired electrons?

Options

A. `Fe^(2+)`
B. `Fe^(3+)`
C. `Co^(2+)`
D. `\Co^(3+)`

Answer

To determine which of the given ions contains the maximum number of unpaired electrons, we will analyze each option step by step.

### Step 1: Analyze Ferrous Ion (Fe²⁺)
1. **Determine the atomic number of Iron (Fe)**: Iron has an atomic number of 26.
2. **Electronic configuration of Fe**: The electronic configuration of Fe is \( [Ar] 4s^2 3d^6 \).
3. **Formation of Fe²⁺**: Fe²⁺ is formed by losing 2 electrons, which are removed from the 4s orbital first.
4. **Electronic configuration of Fe²⁺**: Thus, the electronic configuration of Fe²⁺ is \( [Ar] 3d^6 \).
5. **Count unpaired electrons**: In the 3d subshell, the configuration can be represented as:
- 3d: ↑↓ ↑ ↑ ↑ ↑ (4 unpaired electrons)
- Therefore, Fe²⁺ has **4 unpaired electrons**.

### Step 2: Analyze Ferric Ion (Fe³⁺)
1. **Formation of Fe³⁺**: Fe³⁺ is formed by losing an additional electron from Fe²⁺, resulting in the loss of one more electron from the 3d subshell.
2. **Electronic configuration of Fe³⁺**: The electronic configuration of Fe³⁺ is \( [Ar] 3d^5 \).
3. **Count unpaired electrons**: In the 3d subshell, the configuration can be represented as:
- 3d: ↑ ↑ ↑ ↑ ↑ (3 unpaired electrons)
- Therefore, Fe³⁺ has **5 unpaired electrons**.

### Step 3: Analyze Cobalt(II) Ion (Co²⁺)
1. **Determine the atomic number of Cobalt (Co)**: Cobalt has an atomic number of 27.
2. **Electronic configuration of Co**: The electronic configuration of Co is \( [Ar] 4s^2 3d^7 \).
3. **Formation of Co²⁺**: Co²⁺ is formed by losing 2 electrons, which are removed from the 4s orbital first.
4. **Electronic configuration of Co²⁺**: Thus, the electronic configuration of Co²⁺ is \( [Ar] 3d^7 \).
5. **Count unpaired electrons**: In the 3d subshell, the configuration can be represented as:
- 3d: ↑↓ ↑ ↑ ↑ ↑ (3 unpaired electrons)
- Therefore, Co²⁺ has **3 unpaired electrons**.

### Step 4: Analyze Cobalt(III) Ion (Co³⁺)
1. **Formation of Co³⁺**: Co³⁺ is formed by losing one more electron from Co²⁺, resulting in the loss of one electron from the 3d subshell.
2. **Electronic configuration of Co³⁺**: The electronic configuration of Co³⁺ is \( [Ar] 3d^6 \).
3. **Count unpaired electrons**: In the 3d subshell, the configuration can be represented as:
- 3d: ↑↓ ↑ ↑ ↑ (4 unpaired electrons)
- Therefore, Co³⁺ has **4 unpaired electrons**.

### Summary of Unpaired Electrons
- Fe²⁺: 4 unpaired electrons
- Fe³⁺: 5 unpaired electrons
- Co²⁺: 3 unpaired electrons
- Co³⁺: 4 unpaired electrons

### Conclusion
Comparing the number of unpaired electrons:
- Fe²⁺ has 4
- Fe³⁺ has 5
- Co²⁺ has 3
- Co³⁺ has 4

The ion with the maximum number of unpaired electrons is **Fe³⁺** with **5 unpaired electrons**.

### Final Answer
**The correct answer is: Fe³⁺ (Ferric Ion)**