Inert pair effect is shown by

Options

A. `s`-block
B. `p`-block
C. `d`-block
D. `f`-block

Explanation

**Step-by-Step Solution:**

1. **Understanding Inert Pair Effect:**
The inert pair effect refers to the tendency of the outermost s-electrons (the 'inert pair') to remain non-bonding or inert in heavier elements of the p-block. This phenomenon is observed particularly in the heavier elements of groups 13 to 16 of the periodic table.

2. **Identifying the Groups:**
The inert pair effect is primarily seen in the following groups:
- Boron Family (Group 13)
- Carbon Family (Group 14)
- Nitrogen Family (Group 15)
- Oxygen Family (Group 16)

3. **Valency and Oxidation States:**
Elements in these groups can exhibit multiple oxidation states. For example:
- Boron Family: +1 and +3
- Carbon Family: +2 and +4
- Nitrogen Family: +3 and +5
- Oxygen Family: +2 and +4

4. **Trend Down the Group:**
As you move down a group in the periodic table, the stability of the lower oxidation state (lower valency) increases. This is because the ns² electrons (the inert pair) become more stable and less likely to participate in bonding.

5. **Examples:**
- In the Carbon Family, lead (Pb) predominantly exhibits a +2 oxidation state due to the inert pair effect.
- In the Nitrogen Family, antimony (Sb) and bismuth (Bi) show a preference for the +3 oxidation state.

6. **Conclusion:**
The inert pair effect is characteristic of heavier p-block elements, which exhibit a tendency to show lower oxidation states as compared to their lighter counterparts.

**Final Answer:**
The inert pair effect is shown by heavier p-block elements.

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