Which of the following exhibits inert pair effect ?

Options

A. B
B. Al
C. Tl
D. Sc

Answer

To determine which of the following elements exhibits the inert pair effect, we need to analyze the characteristics of the elements in the context of their oxidation states. The inert pair effect is typically observed in the heavier elements of groups 13, 14, and 15 of the periodic table.

### Step-by-Step Solution:

1. **Understand the Inert Pair Effect**:
- The inert pair effect refers to the tendency of the outermost s-electrons (ns²) to remain non-bonding or inert during chemical reactions, especially in heavier elements. This leads to a preference for lower oxidation states.

2. **Identify the Group Elements**:
- The elements in question belong to group 13. The group consists of the following elements: Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), and Thallium (Tl).

3. **Analyze the Heavier Elements**:
- Among these, Thallium (Tl) is the heaviest element. It can exhibit +1 and +3 oxidation states, with the +1 state being more stable due to the inert pair effect.

4. **Look at the Other Elements**:
- Boron (B) and Aluminum (Al) do not exhibit the inert pair effect as they are lighter elements. Gallium (Ga) and Indium (In) may show some characteristics but are not as pronounced as in Thallium.

5. **Conclusion**:
- Therefore, the element that exhibits the inert pair effect in group 13 is Thallium (Tl).

### Final Answer:
The element that exhibits the inert pair effect is **Thallium (Tl)**.

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