The atomic number of an element represents the number of protons in the nucleus of each atom of that element. It uniquely identifies the element because every atom of a given element has the same number of protons

. In a neutral atom, the atomic number also equals the number of electrons, since the positive charge of protons is balanced by the negative charge of electrons

. Thus, the atomic number determines the element's identity and its position in the periodic table, as elements are arranged in order of increasing atomic number