Which symbol is used to denote the atomic number of an element?

The atomic number of an element is denoted by the symbol Z. This designation represents the number of protons found in the nucleus of an atom, which in turn defines the identity of the element. For example, carbon has an atomic number of 6, indicating it has 6 protons in its nucleus. This is fundamental to understanding both the classification of elements in the periodic table and the basic properties of chemical elements.

In the context of the periodic table, the atomic number is critical because it determines the position of the element. Elements are arranged in order of increasing atomic number, which correlates to their electron configuration and chemical behavior.

The other symbols mentioned represent different concepts in atomic theory. The symbol A typically represents the mass number of an atom, which is the total number of protons and neutrons. N is often used to denote the number of neutrons in a nucleus, while M is less commonly used and does not have a standard meaning in this context related to atomic structure. Therefore, Z is the appropriate and universally accepted symbol for atomic number in chemistry.