Fluorine, because it is more electronegative than chlorine and in periodic table....F>O>N>Cl>Br>I

Electronegativity between F and Cl
F (Fluorine) is the most electronegative element on the periodic table, with an electronegativity value of 3.98. Cl (Chlorine) has an electronegativity value of 3.16. Therefore, Fluorine is more electronegative than Chlorine.

Explanation:

Definition of Electronegativity:
Electronegativity is the ability of an atom to attract shared electrons in a chemical bond. The higher the electronegativity value of an element, the more it attracts electrons towards itself.

Factors affecting Electronegativity:
1. Nuclear charge: The greater the nuclear charge of an atom, the higher its electronegativity.
2. Atomic size: Smaller atoms have higher electronegativity as the nucleus can pull electrons closer.
3. Electron shielding: Effective nuclear charge is reduced by inner electrons, decreasing electronegativity.

Comparison between F and Cl:
- Fluorine has a smaller atomic size and higher nuclear charge compared to Chlorine, making it more electronegative.
- Fluorine's electronegativity value is significantly higher than Chlorine, indicating its stronger ability to attract electrons.
In conclusion, Fluorine is more electronegative than Chlorine due to its smaller atomic size and higher nuclear charge. This difference in electronegativity influences the chemical properties and behavior of these elements in various compounds.