Which one of the following statements is incorrect in relation to ionization enthalpy ?

Options

A. Ionization enthalpy increases for each successive electrons.
B. The greatest increses in ionization enthalpy is experiencedd on removal of electron from core noble gas configuration
C. End of valence electrons is marked by a big jump in ionization enthalpy .
D. Removal of electron from orbitals bearing lower n value is easier than from orbital having higher n value.

Answer

To determine which statement is incorrect in relation to ionization enthalpy, let's analyze each statement step by step.

### Step 1: Understand Ionization Enthalpy
**Definition**: Ionization enthalpy (or ionization energy) is the energy required to remove the outermost electron from an atom in its gaseous state.

**Hint**: Remember that ionization enthalpy is related to the stability of the electron configuration of an atom.

### Step 2: Analyze Each Statement
1. **Statement 1**: Ionization enthalpy increases for each successive electron.
- **Analysis**: This statement is correct. As more electrons are removed, the remaining electrons experience less repulsion and more effective nuclear charge, making it harder to remove additional electrons.

**Hint**: Consider how the effective nuclear charge changes as electrons are removed.

2. **Statement 2**: The greatest increase in ionization enthalpy is experienced on removal of an electron from a core noble gas configuration.
- **Analysis**: This statement is also correct. Noble gases have a stable electron configuration, and removing an electron from such a stable configuration requires significantly more energy.

**Hint**: Think about the stability of noble gas configurations compared to other elements.

3. **Statement 3**: End of valence electrons is marked by a big jump in ionization enthalpy.
- **Analysis**: This statement is correct. When all valence electrons are removed, the next electron removed comes from a more stable, filled inner shell, resulting in a large increase in ionization energy.

**Hint**: Reflect on the concept of electron shells and how removing electrons from different shells affects energy requirements.

4. **Statement 4**: Removal of an electron from orbitals bearing lower n value is easier than from orbitals having higher n value.
- **Analysis**: This statement is incorrect. Electrons in orbitals with lower principal quantum numbers (n) are closer to the nucleus and experience a stronger nuclear attraction. Therefore, it is harder to remove them compared to electrons in orbitals with higher n values.

**Hint**: Compare the distances of electrons in different shells from the nucleus and how this affects their removal.

### Conclusion
The incorrect statement is **Statement 4**: "Removal of an electron from orbitals bearing lower n value is easier than from orbitals having higher n value."

**Final Answer**: Option 4 is the correct answer.