which of the following elements has the highest value of second ionization energy?

Options

A. He
B. Li
C. Ne
D. F

Answer

To determine which element has the highest value of second ionization energy, we need to analyze the electronic configurations and the stability of the resulting ions after the first ionization. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Ionization Energy
- **Definition**: Ionization energy is the energy required to remove an electron from an isolated gaseous atom. The second ionization energy specifically refers to the energy required to remove an electron from a positively charged ion (after the first electron has already been removed).

### Step 2: Analyze the Given Elements
We need to look at the electronic configurations of the elements provided in the options. The elements mentioned are Helium (He), Lithium (Li), Neon (Ne), and Fluorine (F).

1. **Helium (He)**:
- Atomic number: 2
- Electronic configuration: 1s²
- After losing one electron (He⁺): 1s¹
- Second ionization energy: Lower than the first because the remaining electron is in a stable noble gas configuration.

2. **Lithium (Li)**:
- Atomic number: 3
- Electronic configuration: 1s² 2s¹
- After losing one electron (Li⁺): 1s²
- Second ionization energy: Higher because the 1s² configuration is stable and fully filled.

3. **Neon (Ne)**:
- Atomic number: 10
- Electronic configuration: 1s² 2s² 2p⁶
- After losing one electron (Ne⁺): 1s² 2s² 2p⁵
- Second ionization energy: Lower than the first due to the loss of a stable noble gas configuration.

4. **Fluorine (F)**:
- Atomic number: 9
- Electronic configuration: 1s² 2s² 2p⁵
- After losing one electron (F⁺): 1s² 2s² 2p⁴
- Second ionization energy: Not very high as it is still relatively stable but not as high as lithium.

### Step 3: Compare the Second Ionization Energies
- **He**: Lower second ionization energy due to instability after losing the second electron.
- **Li**: Highest second ionization energy due to stability of the 1s² configuration.
- **Ne**: Lower second ionization energy due to the loss of a stable noble gas configuration.
- **F**: Moderate second ionization energy, but lower than that of lithium.

### Conclusion
From the analysis, **Lithium (Li)** has the highest second ionization energy because after losing one electron, it achieves a stable electron configuration (1s²), making it more difficult to remove the second electron.

### Final Answer
The element with the highest value of second ionization energy is **Lithium (Li)**.

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