What is the definition of electronegativity?

Electronegativity is defined as the tendency of an atom to attract electrons in a chemical bond. This property is crucial in determining how atoms interact in chemical reactions. It influences the nature of chemical bonds formed between different atoms, whether they be ionic, covalent, or polar covalent. Atoms with high electronegativity, such as fluorine and oxygen, have a stronger pull on the electrons they share with other atoms, resulting in more polar bonds. This concept is fundamental in understanding molecular structure and properties, as it helps predict how electrons are distributed within molecules.

In this context, the other options do not accurately represent electronegativity. While losing electrons relates more to metals and their reactivity, atom mass and the total number of protons refer to different concepts entirely, such as atomic weight and atomic number, respectively.