Which of following radius order is not correct?

Options

A. `Ti lt Zr ~~Hf`
B. `Sc lt Y ~~La`
C. `B lt Al ~~ Ga lt In ~~ Tl`
D. `O lt N lt S lt P`

Answer

To determine which of the given radius orders is not correct, we need to analyze the trends in atomic radii across periods and down groups in the periodic table.

### Step-by-Step Solution:

1. **Understanding Atomic Radius Trends**:
- Atomic radius increases as you move down a group in the periodic table due to the addition of electron shells.
- Atomic radius decreases as you move from left to right across a period due to increased nuclear charge, which pulls the electrons closer to the nucleus.

2. **Analyzing Each Option**:
- **Option 1**: Titanium (Ti) < Zirconium (Zr) < Hafnium (Hf)
- This is correct. As we move down the group from Ti to Zr to Hf, the atomic radius increases.

- **Option 2**: Scandium (Sc) > Ytterbium (Yb) = Lanthanum (La)
- This is incorrect. Due to lanthanide contraction, Yb and La have similar radii, but Sc should not be greater than Yb. The correct order should be Sc < Yb ≈ La.

- **Option 3**: Boron (B) > Aluminum (Al) ≈ Gallium (Ga) ≈ Indium (In)
- This is incorrect. The atomic radius of boron is less than that of aluminum, as we move down the group, the radius increases. The correct order should be B < Al < Ga < In.

- **Option 4**: Oxygen (O) < Nitrogen (N) < Sulfur (S) < Phosphorus (P)
- This is correct. As we move down the group, the atomic radius increases.

3. **Conclusion**:
- The incorrect radius order is found in **Option 2** and **Option 3**. However, since the question asks for which order is not correct, we can conclude that both options are incorrect, but Option 3 is the most evidently wrong due to the clear trend violation.

### Final Answer:
The radius order that is not correct is **Option 3: Boron > Aluminum ≈ Gallium ≈ Indium**.