What does electronegativity measure?

Electronegativity is a concept that describes the ability of an atom to attract and hold onto electrons when it is participating in a chemical bond. This property is crucial for understanding how atoms interact and form compounds. The greater an atom's electronegativity, the more effectively it can attract electrons that are shared with another atom.

This concept is particularly important in determining the characteristics of various chemical bonds, such as ionic and covalent bonds. For example, in a covalent bond between two atoms, differing electronegativities can lead to unequal sharing of electrons, resulting in polar covalent bonds.

In contrast, the mass of an atom, its size, and its electron affinity do not directly measure the tendency to attract electrons in a bond. While electron affinity relates to the energy change when an electron is added to an atom, it is a different concept from electronegativity. By focusing on the ability of an atom to pull electrons towards itself in a bond, electronegativity serves as a critical metric in chemistry for predicting bond behavior and molecular interactions.