The correct increasing order of electron affinity value of atoms is:

Explanation

The first Electron affinity depends on how strong the bond is formed between the added electron and the nucleus. We have to take into account the effective nuclear charge and the distance between the electron and the nucleus. Since all the elements given have the same effective nuclear charge, we then consider the distance; the greater the distance the smaller the electron affinity. Based on that, we have the order as F>Cl>Br>I.Electron affinity usually decreases as you move down a group on the periodic table because the atoms in that group get larger. This means that when an electron is added to an atom lower in the group, it's further away from the nucleus than it would be in a smaller atom above it. As a result, the electron is less attracted to the nucleus, which leads to a lower electron affinity.ChlorineHas a larger size than fluorine, allowing it to better accommodate electrons.FluorineThe small size of the fluorine atom causes significant repulsion of incoming electrons.