Which element is the most electronegative on the Pauling scale?

Fluorine is the most electronegative element on the Pauling scale.

Electronegativity describes how strongly an atom attracts shared electrons in a chemical bond. Fluorine receives a value of 3.98 on the Pauling scale, the highest value for any element. Its small atomic radius and strong effective nuclear attraction help explain this powerful pull on bonding electrons.

Fluorine is a pale yellow gas at room temperature and has atomic number 9. It is the most reactive halogen and does not occur freely in nature in significant amounts because it readily forms compounds. Fluoride ions occur in minerals such as fluorite and in many other substances.

Although elemental fluorine is extremely hazardous and corrosive, controlled fluoride compounds have important uses. Fluoride is added to some dental products, and fluorinated chemicals are used in materials, medicines, and industrial processes. Electronegativity is not the same as reactivity, though the two properties are often related.