Which electronic configuration of an element has abnormally high difference between second and third ionization enthalpies ?

Options

A. `1s^(2) 2s^(2) 2p^(6)3s^(1)`
B. `1s^(2) 2s^(2)2p^(6)3s^(2)3p^(1)`
C. `1s^(2)2s^(2)2p^(6),3s^(2)3p^(2)`
D. `1s^(2)2s^(2)2p^(6)3s^(2)`

Answer

To determine which electronic configuration of an element has an abnormally high difference between the second and third ionization enthalpies, we need to analyze the given electronic configurations and their implications on ionization energies.

### Step-by-Step Solution:

1. **Understanding Ionization Enthalpy**:
- Ionization enthalpy is the energy required to remove an electron from an atom in the gaseous state. The first ionization enthalpy (IE1) involves removing the first electron, the second ionization enthalpy (IE2) involves removing the second electron, and so forth.

2. **Identifying the Configurations**:
- We have four options to evaluate. We will analyze the electronic configurations for each option and determine the difference between the second and third ionization enthalpies.

3. **Analyzing Each Option**:
- **Option 1**: Configuration is 1s² 2s² 2p⁶ 3s¹.
- IE1: 1s² 2s² 2p⁶ 3s¹ → 1s² 2s² 2p⁶ (removal of 3s electron)
- IE2: 1s² 2s² 2p⁶ → 1s² 2s² 2p⁵ (removal of another electron from 2p)
- IE3: 1s² 2s² 2p⁵ → 1s² 2s² 2p⁴ (removal of another electron from 2p)
- Difference: IE2 and IE3 are not abnormally high.

- **Option 2**: Configuration is 1s² 2s² 2p⁶ 3s².
- IE1: 1s² 2s² 2p⁶ 3s² → 1s² 2s² 2p⁶ 3s¹
- IE2: 1s² 2s² 2p⁶ 3s¹ → 1s² 2s² 2p⁶ (removal of 3s electron)
- IE3: 1s² 2s² 2p⁶ → 1s² 2s² 2p⁵ (removal from 2p)
- Difference: Not abnormally high.

- **Option 3**: Configuration is 1s² 2s² 2p⁶ 3s² 3p¹.
- IE1: 1s² 2s² 2p⁶ 3s² 3p¹ → 1s² 2s² 2p⁶ 3s²
- IE2: 1s² 2s² 2p⁶ 3s² → 1s² 2s² 2p⁶ 3s¹
- IE3: 1s² 2s² 2p⁶ 3s¹ → 1s² 2s² 2p⁶ (removal from 2p)
- Difference: Not abnormally high.

- **Option 4**: Configuration is 1s² 2s² 2p⁶ 3s² 3p⁵.
- IE1: 1s² 2s² 2p⁶ 3s² 3p⁵ → 1s² 2s² 2p⁶ 3s² 3p⁴
- IE2: 1s² 2s² 2p⁶ 3s² 3p⁴ → 1s² 2s² 2p⁶ 3s² 3p³
- IE3: 1s² 2s² 2p⁶ 3s² 3p³ → 1s² 2s² 2p⁶ 3s² (removal from 3p)
- **Key Point**: After the second ionization, the configuration reaches a noble gas state (1s² 2s² 2p⁶), resulting in a significant increase in stability. Thus, removing the third electron requires a much larger amount of energy.

4. **Conclusion**:
- The electronic configuration that shows an abnormally high difference between the second and third ionization enthalpies is **Option 4** (1s² 2s² 2p⁶ 3s² 3p⁵).