Which electronic configuration of neutral atoms of the highest first ionisation energy?

Options

A. `1s^2 2s^2 2p^4`
B. `1s^2 2s^2 2p^3`
C. `1s^2 2s^2 2p^2`
D. `1s^2 2s^2 2p^1`

Explanation

To determine which electronic configuration corresponds to the neutral atom with the highest first ionization energy, we will analyze the given electronic configurations step by step.

### Step-by-Step Solution:

1. **Identify the Electronic Configurations**: The question provides four electronic configurations. Let's list them:
- A: 1s² 2s² 2p⁴
- B: 1s² 2s² 2p³
- C: 1s² 2s² 2p²
- D: 1s² 2s² 2p¹

2. **Determine the Atomic Numbers**: From the electronic configurations, we can identify the atomic numbers:
- A (1s² 2s² 2p⁴) corresponds to Oxygen (atomic number 8).
- B (1s² 2s² 2p³) corresponds to Nitrogen (atomic number 7).
- C (1s² 2s² 2p²) corresponds to Carbon (atomic number 6).
- D (1s² 2s² 2p¹) corresponds to Boron (atomic number 5).

3. **Understand Ionization Energy**: Ionization energy is the energy required to remove the most loosely bound electron from an isolated gaseous atom. Generally, the ionization energy increases across a period (left to right) and decreases down a group (top to bottom) in the periodic table.

4. **Analyze the Configurations**:
- Oxygen (A) has a configuration of 1s² 2s² 2p⁴, which means it has 6 valence electrons and is close to achieving a full octet.
- Nitrogen (B) has a configuration of 1s² 2s² 2p³, which is a half-filled configuration. Half-filled and fully filled configurations are generally more stable and require more energy to remove an electron.
- Carbon (C) has a configuration of 1s² 2s² 2p², and Boron (D) has 1s² 2s² 2p¹, both of which have lower ionization energies compared to Nitrogen and Oxygen.

5. **Conclusion**: Among the configurations analyzed, Nitrogen (1s² 2s² 2p³) has the highest first ionization energy due to its half-filled p orbital, which provides extra stability. Thus, the answer is:
- **B: 1s² 2s² 2p³ (Nitrogen)**