Which of the following does not react with florime?

Options

A. Kr
B. At
C. Xe
D. All of these

Explanation

To determine which of the following elements does not react with fluorine, we need to analyze the properties of the elements given: krypton, argon, and xenon.

### Step-by-Step Solution:

1. **Identify the Elements**: The elements provided are krypton (Kr), argon (Ar), and xenon (Xe). These elements belong to Group 18 of the periodic table, also known as the noble gases.

2. **Understand Noble Gases**: Noble gases are characterized by their complete valence electron shells, which make them very stable and generally unreactive.

3. **Ionization Energy Trend**: As we move down the group from helium to xenon, the ionization energy decreases. This means that the ability to lose an electron (and thus react) becomes easier for the heavier noble gases (like xenon and krypton) compared to the lighter ones (like argon and helium).

4. **Reactivity with Fluorine**: Fluorine is a highly electronegative element and is known to react with many elements. However, due to their stable electron configurations, noble gases do not readily react with fluorine.

5. **Evaluate Each Element**:
- **Argon (Ar)**: Has a high ionization energy and does not react with fluorine.
- **Krypton (Kr)**: Has a lower ionization energy than argon and can react with fluorine.
- **Xenon (Xe)**: Also has a lower ionization energy than argon and can react with fluorine.

6. **Conclusion**: Among the three elements, argon is the one that does not react with fluorine due to its higher ionization energy and stable electron configuration.

### Final Answer:
**Argon (Ar) does not react with fluorine.**