Describe the role of the atomic number in determining the identity of an element.

The atomic number represents the number of protons in an atom's nucleus. This number is unique to each element and dictates its chemical properties, effectively identifying the element.
The atomic number (Z) is a fundamental property of an atom. It defines the number of protons, which in turn determines the element's identity. For example, all atoms with 6 protons are carbon atoms, regardless of their number of neutrons or electrons. Changing the number of protons changes the element itself.