What is meant by the term atomic number?

The term atomic number refers specifically to the number of protons present in the nucleus of an atom. This fundamental characteristic uniquely identifies each element on the periodic table. For example, hydrogen has an atomic number of 1, which means it has one proton, while carbon has an atomic number of 6, indicating it has six protons.

The atomic number is crucial because it determines the element's chemical properties and its position in the periodic table. It also influences how the element behaves during chemical reactions, as the number of protons (and therefore the number of electrons in a neutral atom) affects the atom's overall charge and its interactions with other atoms.

Knowing that the atomic number is effectively equal to the number of protons helps to clarify concepts such as electron configuration and ionization, further reinforcing the importance of this definition in the study of chemistry.