Which chemical element is the most electronegative?

Fluorine is generally considered the most electronegative chemical element. On the Pauling scale, it has an electronegativity of 3.98, meaning it attracts shared electrons more strongly than any other reactive element.

Fluorine’s position explains much of its strength: it is a very small atom near the upper-right corner of the periodic table, with seven electrons in its outer shell. Its nucleus exerts a strong pull on bonding electrons, and the atom needs only one more electron to reach a filled outer shell. This makes fluorine exceptionally reactive and gives compounds such as hydrogen fluoride and carbon–fluorine molecules strongly polarized bonds.

Electronegativity is not measured directly and depends on the scale used. Linus Pauling introduced the best-known scale in 1932. Noble gases are sometimes assigned values on other scales; on the Allen scale, neon can rank above fluorine. However, standard school and general-chemistry questions use the Pauling convention and usually exclude noble gases, making fluorine the canonical answer. Chlorine and oxygen are also highly electronegative, but both rank below fluorine.