The most electronegative element on the periodic table is fluorine. It has an electronegativity value of 3.98 on the Pauling scale, meaning it strongly attracts electrons in chemical bonds. This high electronegativity makes fluorine highly reactive, often forming compounds with other elements, even those that are typically stable. Its reactivity and ability to form strong bonds are essential in various applications, including the production of fluorinated compounds used in pharmaceuticals and industrial processes.