The atomic number of an element corresponds to the number of protons in the nucleus of an atom of that element. It is a unique identifier for each element on the periodic table.
Each element has a different number of protons in its nucleus, and the atomic number determines the element's position in the periodic table. For example, hydrogen has an atomic number of 1 because it has one proton in its nucleus, while carbon has an atomic number of 6 because it has six protons.
The atomic number is denoted by the symbol "Z" and is typically written as a subscript before the chemical symbol of the element. It is an essential characteristic of an element and helps to define its chemical and physical properties.