Which of the following elements has the highest electronegativity?

Fluorine is the element with the highest electronegativity due to its atomic structure and position on the periodic table. Electronegativity is a measure of an atom's ability to attract and hold onto electrons within a chemical bond. Fluorine is located in Group 17 (the halogens) and is the most electronegative element on the Pauling scale with a value of approximately 4.0.

One reason for this high electronegativity is that fluorine has a small atomic radius and a relatively high effective nuclear charge. This means that the nucleus of the fluorine atom exerts a strong attractive force on the valence electrons. Fluorine also has seven valence electrons and needs only one additional electron to achieve a stable octet configuration, making it highly effective at attracting electrons from other atoms during bond formation.

By comparison, while oxygen, nitrogen, and chlorine have significant electronegativities, they do not reach the level of fluorine. Oxygen is the second most electronegative element, but it is not as effective in attracting electrons as fluorine is. Hence, the distinction of fluorine as the element with the highest electronegativity is well-established in chemistry.