Moseley's number

Moseley's number, or atomic number, refers to the number of protons in an atom's nucleus. It uniquely identifies each chemical element and determines its properties. For example, all hydrogen atoms have one proton, so hydrogen's atomic number is 1, while carbon has six protons, so its number is 6. Moseley's work in the early 20th century showed that elements can be ordered by increasing atomic number, which helped clarify the periodic table's organization and confirmed the relationship between atomic structure and chemical behavior.