Why chlorine has highest electron affinity than fluorine?
This is because the atomic radius increases down a group. The electron gained ends up in the outermost shell. ... Fluorine, which is higher up the group then chlorine, has a lower electron affinity. This is because the electrons in the outermost shell of a fluorine atom are closer together.
Look at the periodic table the element next at the right of Cl is the Ar and the atomic mass is 39.948 is bigger than the Cl 35.45. All the elements after that has mases bigger than Cl.
