Which of the following matched correctly: `{:(,I.P.,,Reason,),((A),NgtO,,"Half filled configuration",),((B),ZrltHf,,"Lanthanoid contraction",),((C),NagtK,,Z_("eff"),),((D),AlltGa,,"Transition contraction",):}`

Options

A. Only A
B. A, B, C, D
C. Only C
D. Only C, D

Answer

To solve the question regarding the correct matches between ionization potential (I.P.) and their respective reasons, we will analyze each option step by step.

### Step 1: Analyze Option A
- **Elements:** Nitrogen (N) and Oxygen (O)
- **Claim:** N has a greater ionization potential than O.
- **Reason:** Half-filled configuration.

**Analysis:**
- Nitrogen has the electronic configuration of 2s² 2p³ (half-filled), while Oxygen has 2s² 2p⁴ (not half-filled).
- Half-filled configurations are more stable due to symmetry and exchange energy.
- Therefore, N has a higher ionization potential than O.

**Conclusion:** Option A is correctly matched.

### Step 2: Analyze Option B
- **Elements:** Zirconium (Zr) and Hafnium (Hf)
- **Claim:** Zr has a lower ionization potential than Hf.
- **Reason:** Lanthanoid contraction.

**Analysis:**
- As we move from Zr to Hf, we encounter the f-block elements (lanthanides) which cause poor shielding due to the filling of the f-orbitals.
- This results in an increase in effective nuclear charge, leading to a higher ionization potential for Hf compared to Zr.

**Conclusion:** Option B is correctly matched.

### Step 3: Analyze Option C
- **Elements:** Sodium (Na) and Potassium (K)
- **Claim:** Na has a greater ionization potential than K.
- **Reason:** Z_eff (effective nuclear charge).

**Analysis:**
- As we move down the group from Na to K, the atomic size increases, and the effective nuclear charge felt by the outermost electron decreases.
- This results in a lower ionization potential for K compared to Na.

**Conclusion:** Option C is correctly matched.

### Step 4: Analyze Option D
- **Elements:** Aluminum (Al) and Gallium (Ga)
- **Claim:** Ga has a greater ionization potential than Al.
- **Reason:** Transition contraction.

**Analysis:**
- Gallium has d-electrons, which lead to a poor shielding effect. This results in a higher effective nuclear charge compared to Al, thus increasing the ionization potential of Ga.

**Conclusion:** Option D is correctly matched.

### Final Conclusion
All options A, B, C, and D are correctly matched with their respective reasons.

### Final Answer
**All options are correctly matched.**

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