Which one of the following has maximum number of unpaired electrons

Options

A. `Mg^(2+)`
B. `Ti^(3+)`
C. `V^(3+)`
D. `Fe^(2+)`

Explanation

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

### Step 1: Analyze Magnesium (Mg)
- The electronic configuration of magnesium (Mg) is:
\[ \text{Mg: } 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \]
- When magnesium is in the +2 oxidation state (Mg²⁺), it loses the two 3s electrons:
\[ \text{Mg}^{2+}: 1s^2 \, 2s^2 \, 2p^6 \]
- In Mg²⁺, all electrons are paired.
- **Number of unpaired electrons (n) = 0**

### Step 2: Analyze Titanium (Ti)
- The electronic configuration of titanium (Ti) is:
\[ \text{Ti: } 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^2 \]
- For titanium in the +3 oxidation state (Ti³⁺), it loses the two 4s electrons and one 3d electron:
\[ \text{Ti}^{3+}: 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 3d^1 \]
- In Ti³⁺, there is 1 unpaired electron in the 3d subshell.
- **Number of unpaired electrons (n) = 1**

### Step 3: Analyze Iron (Fe)
- The electronic configuration of iron (Fe) is:
\[ \text{Fe: } 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^6 \]
- For iron in the +2 oxidation state (Fe²⁺), it loses the two 4s electrons:
\[ \text{Fe}^{2+}: 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 3d^6 \]
- The 3d subshell will have the following configuration:
- Filling order: ↑ ↑ ↑ ↑ ↑ (6 electrons in 3d)
- The 3d subshell has 4 unpaired electrons.
- **Number of unpaired electrons (n) = 4**

### Conclusion
After analyzing all the options:
- Mg²⁺ has 0 unpaired electrons.
- Ti³⁺ has 1 unpaired electron.
- Fe²⁺ has 4 unpaired electrons.

Thus, the element with the maximum number of unpaired electrons is **Fe²⁺** with **4 unpaired electrons**.

### Final Answer
**Fe²⁺ has the maximum number of unpaired electrons (4).**

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