Atomic Number

Atomic number or Nuclear charge

(i) The number of protons present in the nucleus of the atom is called atomic number (Z).

(ii) It was determined by Moseley as, √v = a (Z-b)  or aZ-ab 

Where, v = X- ray’s frequency Z = atomic number of the metal a& b are constant.

(iii)    Atomic number = Number of positive charge on nucleus = Number of protons in nucleus = Number of electrons in neutral atom.

(iv) Two different elements can never have identical atomic number.