Here's why:
* Electronegativity: Fluorine has the highest electronegativity of all elements. This means it has a strong attraction for electrons, making it highly reactive.
* Small Atomic Size: Fluorine has the smallest atomic radius among the halogens. This leads to a high electron density and stronger electrostatic interactions, further enhancing its reactivity.
* Bond Strength: The fluorine-fluorine bond is relatively weak compared to the bonds in other halogens. This means it's easier to break the bond and form new bonds with other elements, making fluorine highly reactive.
Therefore, the order of reactivity is:
Fluorine > Chlorine > Bromine
