The atomic number of an atom corresponds to what characteristic?

The atomic number of an atom is significant because it corresponds directly to the number of protons located in the nucleus. This fundamental property is what distinguishes one element from another on the periodic table. For example, carbon has an atomic number of 6, which means it has six protons in its nucleus. This number is crucial because it determines the chemical properties of the element and its position on the periodic table.

The atomic number not only defines the identity of the element but also influences the number of electrons in a neutral atom, which is equal to the number of protons. Thus, the atomic number plays a pivotal role in understanding an element's behavior in chemical reactions and bonding.

In contrast, the total mass of the atom is related to both protons and neutrons, and the number of neutrons alone does not define the atomic number. The number of electrons, while important, can vary in ions and do not affect the atomic number. Therefore, the atomic number's specific association with the number of protons makes this choice the correct answer.