In which of the following paisr, first member has higher first IP
(a) N,O (b) B,Be ( c) Al,Ga
(d) F,CI (e) Zn,Ga (f)`F^(-),CI^(-)`
Correct option is

Options

A. a,c,f,d
B. a,d,e
C. b,d,e,f
D. a,d,e,f

Answer

To determine which of the given pairs has the first member with the highest first ionization potential (IP), we will analyze each pair step by step.

### Step 1: Analyze Pair (a) N, O
- **Electronic configurations**:
- Nitrogen (N): 1s² 2s² 2p³
- Oxygen (O): 1s² 2s² 2p⁴
- **Comparison**: Nitrogen has a half-filled p subshell, which is more stable than the fully filled p subshell of oxygen. Therefore, it is more difficult to remove an electron from nitrogen than from oxygen.
- **Conclusion**: N has a higher first IP than O.

### Step 2: Analyze Pair (b) B, Be
- **Electronic configurations**:
- Boron (B): 1s² 2s² 2p¹
- Beryllium (Be): 1s² 2s²
- **Comparison**: Beryllium has a completely filled 2s subshell, making it more stable than boron. Thus, it requires more energy to remove an electron from beryllium.
- **Conclusion**: Be has a higher first IP than B.

### Step 3: Analyze Pair (c) Al, Ga
- **Electronic configurations**:
- Aluminum (Al): 1s² 2s² 2p⁶ 3s² 3p¹
- Gallium (Ga): 1s² 2s² 2p⁶ 3s² 3p¹ 3d¹⁰
- **Comparison**: Although Ga is below Al in the periodic table, it has d-orbitals that provide poor shielding, leading to a higher IP for Ga compared to Al.
- **Conclusion**: Ga has a higher first IP than Al.

### Step 4: Analyze Pair (d) F, Cl
- **Electronic configurations**:
- Fluorine (F): 1s² 2s² 2p⁵
- Chlorine (Cl): 1s² 2s² 2p⁶ 3s² 3p⁵
- **Comparison**: Fluorine is above chlorine in the periodic table, and as we move down a group, IP decreases. Therefore, F has a higher first IP than Cl.
- **Conclusion**: F has a higher first IP than Cl.

### Step 5: Analyze Pair (e) Zn, Ga
- **Electronic configurations**:
- Zinc (Zn): 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s²
- Gallium (Ga): 1s² 2s² 2p⁶ 3s² 3p¹ 3d¹⁰
- **Comparison**: Zinc has a completely filled d subshell and is more stable than gallium. Thus, it has a higher IP.
- **Conclusion**: Zn has a higher first IP than Ga.

### Step 6: Analyze Pair (f) F⁻, Cl⁻
- **Comparison**: When comparing anions, the size and electron-electron repulsion play a role. F⁻ is smaller than Cl⁻, leading to greater electron-electron repulsion in F⁻, making it harder to add another electron.
- **Conclusion**: F⁻ has a higher first IP than Cl⁻.

### Final Conclusion
The pairs where the first member has a higher first ionization potential are:
- (a) N, O
- (d) F, Cl
- (e) Zn, Ga
- (f) F⁻, Cl⁻

The correct option is **(d) F, Cl**.