In group 14 , which element show inert pair effect ?

Options

A. Si
B. Pb
C. C
D. Ge

Answer

### Step-by-Step Solution:

1. **Understanding Group 14 Elements**:
Group 14 of the periodic table includes the elements Carbon (C), Silicon (Si), Germanium (Ge), Tin (Sn), and Lead (Pb).

2. **Defining Inert Pair Effect**:
The inert pair effect refers to the tendency of the two electrons in the outermost s-orbital (ns²) to remain non-bonding or "inert" in heavier elements. This results in a lower oxidation state being more stable than the higher oxidation state.

3. **Analyzing the Electronic Configuration**:
The general electronic configuration of Group 14 elements is ns² np². As we move down the group, the principal quantum number increases, and additional d and f orbitals are filled.

4. **Impact of Poor Shielding**:
In heavier elements, such as Lead (Pb), the presence of f-orbitals (specifically 4f in the 6th period) leads to poor shielding of the nucleus. This means that the effective nuclear charge (Z-effective) felt by the s-electrons increases.

5. **Resulting Inertness of s Electrons**:
Due to the increased Z-effective, the s-electrons are held more tightly by the nucleus and do not participate in bonding. This results in the s-electrons being "inert" and leads to the stability of the +2 oxidation state over the +4 oxidation state.

6. **Identifying the Element**:
Among the Group 14 elements, Lead (Pb) is the one that exhibits the inert pair effect due to its position in the periodic table and the influence of the filled f-orbitals.

### Conclusion:
In Group 14, Lead (Pb) shows the inert pair effect.

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