The element having very high ionization enthalpy but zero electron affinity is :-

Options

A. H
B. F
C. He
D. Be

Answer

To solve the question of identifying the element with very high ionization enthalpy but zero electron affinity, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Ionization Enthalpy**:
- Ionization enthalpy (or ionization energy) is the amount of energy required to remove an electron from an isolated gaseous atom. Higher ionization energy indicates that it is more difficult to remove an electron.

2. **Understand Electron Affinity**:
- Electron affinity is the energy change that occurs when an atom gains an electron. A zero electron affinity means that the atom does not have a tendency to gain an electron, indicating stability in its current electronic configuration.

3. **Identify Noble Gases**:
- Noble gases have a complete valence shell, making them very stable. They typically exhibit high ionization energies because removing an electron from a stable configuration requires a significant amount of energy.

4. **Examine Helium**:
- Helium has the electronic configuration of 1s², which is a noble gas configuration. This means it has a full outer shell and is very stable.

5. **Check Ionization Energy of Helium**:
- Because helium is stable with a full outer shell, it has a very high ionization enthalpy. It requires a large amount of energy to remove one of its electrons.

6. **Check Electron Affinity of Helium**:
- Helium has zero electron affinity because it does not need to gain an electron to achieve stability; it is already stable with its current configuration. There is no tendency to attract an additional electron.

7. **Conclusion**:
- Based on the above analysis, the element that has very high ionization enthalpy and zero electron affinity is **Helium (He)**.

### Final Answer:
The element having very high ionization enthalpy but zero electron affinity is **Helium (He)**.

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