What does electronegativity measure in a chemical compound?

Electronegativity is a measure of the tendency of an atom in a chemical compound to attract electrons towards itself when it is involved in a bond with another atom. The concept is particularly vital in understanding how different elements interact and bond with one another, influencing the properties of the resulting compounds. Elements with high electronegativity values, such as fluorine and oxygen, have a strong ability to pull electron density towards themselves, which can lead to polar covalent bonds.

In contrast, while atomic mass refers to the mass of an atom and is crucial for stoichiometric calculations, it doesn’t provide insight into the electron-attracting power of an atom. Electron affinity is related but refers specifically to the energy change when an electron is added to an atom, rather than the atom's ability to attract electrons in a bond. The rate of reaction pertains to the speed at which a chemical reaction occurs and is influenced by various factors such as temperature and concentration, rather than the atom's intrinsic electron-attracting capacity. Thus, the correct understanding of electronegativity focuses primarily on its role in indicating an atom’s ability to attract electrons.