Which of the following order is not correct ?

Options

A. `IE(I)` of `Be gt IE(I)` of `B` but `IE(II)` of `Be lt IE(II)` of `B`
B. `IE(I)` of `Be lt IE(I)` of `B` but `IE(II)` of `Be lt IE(II)` of `B`
C. `IE(II)` of `O gt IE(II)` of `N`
D. `IE(I)` of `Mg gt IE(I)` of `Al`

Explanation

To determine which of the given orders is not correct, we need to analyze the ionization energies of the elements mentioned in the options. Let's break it down step by step.

### Step-by-Step Solution:

1. **Understanding Ionization Energy**:
- Ionization energy is the energy required to remove the outermost electron from an atom. Generally, elements with a stable electronic configuration (like fully filled or half-filled orbitals) have higher ionization energies.

2. **Analyzing the First Order (Beryllium vs. Boron)**:
- **Electronic Configurations**:
- Beryllium (Be): 1s² 2s²
- Boron (B): 1s² 2s² 2p¹
- Beryllium has a fully filled 2s orbital, while Boron has an incomplete p orbital.
- **Conclusion**: The first ionization energy of Beryllium is greater than that of Boron. This order is correct.

3. **Analyzing the Second Order (Second Ionization Energy of Beryllium vs. Boron)**:
- After losing one electron:
- Beryllium: 1s² 2s¹
- Boron: 1s² 2s²
- Beryllium has a stable filled 1s orbital, while Boron has a stable filled 2s orbital.
- **Conclusion**: The second ionization energy of Boron is greater than that of Beryllium. This order is incorrect as stated.

4. **Analyzing the Third Order (Second Ionization Energy of Oxygen vs. Nitrogen)**:
- **Electronic Configurations**:
- Oxygen (O): 1s² 2s² 2p⁴
- Nitrogen (N): 1s² 2s² 2p³
- After losing one electron:
- Oxygen: 1s² 2s² 2p³ (half-filled)
- Nitrogen: 1s² 2s² 2p²
- Oxygen becomes more stable after losing an electron, thus has a higher second ionization energy than Nitrogen.
- **Conclusion**: This order is correct.

5. **Analyzing the Fourth Order (Ionization Energy of Magnesium vs. Aluminium)**:
- **Electronic Configurations**:
- Magnesium (Mg): 1s² 2s² 2p⁶ 3s²
- Aluminium (Al): 1s² 2s² 2p⁶ 3s² 3p¹
- Magnesium has a fully filled 3s orbital, while Aluminium has an incomplete 3p orbital.
- **Conclusion**: Magnesium has a higher ionization energy than Aluminium. This order is correct.

### Final Conclusion:
The order that is not correct is the second order regarding the second ionization energies of Beryllium and Boron.