While going down in the group of non-metals (14, 15, 16 and 17) the electronegative character of non-metals decreases. Typical example is of group 15 elements. The elements nitrogen (2nd period) and phosphorus (3rd period) are non-metals and their oxides are acidic in nature. The elements arsenic (4th period) and antimony (5th period) are metalloids and their oxides are amphoteric in nature. However, bismuth (6th period) is a metal. Thus, we can see that the electronegative character (non-metallic character) of elements gradually decreases and ultimately the last element becomes metal. In case of group 17 of halogens, the first member of the group i.e., fluorine is most non-metallic in character and last member of group, i.e., astatine is least non-metallic in character. In other words, the electronegative nature of the elements decreases as we move down the group.
Which is the least electronegative element among the following ?

Options

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

Answer

To determine the least electronegative element among the given options (Fluorine, Chlorine, Bromine, and Iodine), we can follow these steps:

### Step-by-Step Solution:

1. **Understand Electronegativity**: Electronegativity is the ability of an atom to attract electrons towards itself when it is bonded to another atom. The higher the electronegativity, the stronger the atom's ability to attract electrons.

2. **Identify the Group**: The elements mentioned (Fluorine, Chlorine, Bromine, and Iodine) belong to Group 17 of the periodic table, known as the halogens.

3. **Trend in Electronegativity**: As we move down a group in the periodic table, the size of the atoms increases due to the addition of electron shells. This increase in size leads to a decrease in electronegativity because the outer electrons are further from the nucleus and experience a weaker attraction.

4. **List the Elements in Order**:
- Fluorine (F) - highest electronegativity
- Chlorine (Cl) - lower than Fluorine
- Bromine (Br) - lower than Chlorine
- Iodine (I) - lowest electronegativity among these

5. **Conclusion**: Based on the trend, Iodine (I) is the least electronegative element among the given options.

### Final Answer:
The least electronegative element among the given options is **Iodine (I)**.

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