Maximum number of unpaired electrons are present in:

Options

A. Ti2+
B. Sc3+
C. Cr3+
D. Mn2+

Explanation

To determine the maximum number of unpaired electrons in the given ions, we will analyze each ion's electronic configuration step by step.

### Step 1: Determine the electronic configuration of Ti²⁺ (Titanium)
- Atomic number of Titanium (Ti) = 22
- Ground state electronic configuration: \( \text{Ti} = [\text{Ar}] 4s^2 3d^2 \)
- For Ti²⁺, we remove 2 electrons from the 4s orbital first:
\[ \text{Ti}^{2+} = [\text{Ar}] 3d^2 \]
- Number of unpaired electrons in Ti²⁺ = 2 (both 3d electrons are unpaired).

### Step 2: Determine the electronic configuration of Sc³⁺ (Scandium)
- Atomic number of Scandium (Sc) = 21
- Ground state electronic configuration: \( \text{Sc} = [\text{Ar}] 4s^2 3d^1 \)
- For Sc³⁺, we remove 3 electrons (2 from 4s and 1 from 3d):
\[ \text{Sc}^{3+} = [\text{Ar}] \]
- Number of unpaired electrons in Sc³⁺ = 0 (no electrons left).

### Step 3: Determine the electronic configuration of Cr³⁺ (Chromium)
- Atomic number of Chromium (Cr) = 24
- Ground state electronic configuration: \( \text{Cr} = [\text{Ar}] 4s^2 3d^4 \)
- For Cr³⁺, we remove 3 electrons (2 from 4s and 1 from 3d):
\[ \text{Cr}^{3+} = [\text{Ar}] 3d^3 \]
- Number of unpaired electrons in Cr³⁺ = 3 (all 3d electrons are unpaired).

### Step 4: Determine the electronic configuration of Mn²⁺ (Manganese)
- Atomic number of Manganese (Mn) = 25
- Ground state electronic configuration: \( \text{Mn} = [\text{Ar}] 4s^2 3d^5 \)
- For Mn²⁺, we remove 2 electrons (both from 4s):
\[ \text{Mn}^{2+} = [\text{Ar}] 3d^5 \]
- Number of unpaired electrons in Mn²⁺ = 5 (all 5 3d electrons are unpaired).

### Summary of Unpaired Electrons:
- Ti²⁺: 2 unpaired electrons
- Sc³⁺: 0 unpaired electrons
- Cr³⁺: 3 unpaired electrons
- Mn²⁺: 5 unpaired electrons

### Conclusion:
The maximum number of unpaired electrons is found in Mn²⁺, which has **5 unpaired electrons**.

### Final Answer:
**Option D: Mn²⁺ (5 unpaired electrons)**

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