Which is //are likely to show inert pair effect ?

Options

A. ` K`
B. `Mg`
C. Ga`
D. `Pb`

Answer

### Step-by-Step Text Solution:

1. **Understanding Inert Pair Effect**: The inert pair effect refers to the tendency of the s-electrons (specifically the ns electrons) in the outermost shell of heavier elements to remain non-bonding or inert during chemical reactions. This results in a lower oxidation state being more stable than the higher oxidation state.

2. **Identifying Elements**: The inert pair effect is primarily observed in the heavier elements of the p-block, particularly in Group 14 (the Carbon Family) and Group 13 elements.

3. **Examples of Elements**:
- **Thallium (Tl)**: Thallium can exhibit oxidation states of +1 and +3. The +1 state (Tl⁺) is more stable than the +3 state (Tl³⁺) due to the inert pair effect, where the 6s electrons are reluctant to participate in bonding.
- **Lead (Pb)**: Lead can exist in oxidation states of +2 and +4. The +2 state (Pb²⁺) is more stable than the +4 state (Pb⁴⁺) for similar reasons.
- **Bismuth (Bi)**: Bismuth can show oxidation states of +3 and +5. The +3 state (Bi³⁺) is more stable than the +5 state (Bi⁵⁺) due to the inert pair effect.

4. **Conclusion**: The elements likely to show the inert pair effect include Thallium (Tl), Lead (Pb), and Bismuth (Bi). This effect leads to the stability of lower oxidation states in these elements.