Which of the following elements does not show disproportionation tendency?

Options

A. Cl
B. Br
C. F
D. I

Explanation

To determine which of the following elements does not show disproportionation tendency, we first need to understand what disproportionation means. Disproportionation is a reaction in which a single substance is simultaneously oxidized and reduced, resulting in the formation of two different products.

### Step-by-Step Solution:

1. **Understand Disproportionation**: Disproportionation occurs when an element in a particular oxidation state is transformed into two different oxidation states in a redox reaction.

2. **Identify the Elements**: The elements in question are likely to be halogens, which include Chlorine (Cl), Bromine (Br), and Fluorine (F).

3. **Examine Oxidation States**:
- **Chlorine (Cl)**: Can exhibit oxidation states from -1 to +7. This means Cl can undergo disproportionation.
- **Bromine (Br)**: Can exhibit oxidation states from -1 to +7 as well. Thus, Br can also undergo disproportionation.
- **Fluorine (F)**: Only exhibits oxidation states of -1 and 0. Fluorine is the most electronegative element and does not show a positive oxidation state. Therefore, it cannot undergo disproportionation.

4. **Conclusion**: Since Fluorine does not have variable oxidation states and cannot undergo disproportionation, it is the element that does not show disproportionation tendency.

### Final Answer:
The element that does not show disproportionation tendency is **Fluorine (F)**.