The English scientist Henry Moseley demonstrated, with the help of the experiments done using X-ray tube, that the atomic number (Z) of an element corresponds to the positive charge on the nucleus or the number of the protons in the nucleus of the atom or that element. He suggested that ‘atomic number’ is more. fundamental property of an element rather than its atomic mass. On the basis of this research, elements were arranged in the order of their increasing atomic numbers in a more systematic way. Accordingly, the statement of the modern periodic law was stated.
