So once again, electronegativity arises from effective nuclear charge. The more dense electrons an atom has, the larger the effective nuclear charge is, the more electronegative the atom. And that's exactly why electronegativity increases as we go from lithium to fluorine. Because the number of bounced electrons found in each atom increases as we go from left to right on our periodic table. Also the ratio of bounce electrons to the innermost electrons also increases. So let's take lithium, for example, and let's compare it to fluorine.