How did Mosley's work on atomic number show that atomic number is a fundamental property better than atomic weight?

Explanation

Mosley.s equation is
`sqrtv= a(Z-b)` where v= frequency, Z= atomic number a, b= constants
A plot of `sqrtv` against .Z. gives a straight line
However, no such relationship was obtained when the plot was drawn between frequency and the atomic mass. The atomic number of the elements, according to Mosley, stands for serival numbers of the elements in the periodic table. As the atomic number of the elements increase, the wavelength of characteristic X-rays decrease. Mosley concluded that there is a fundamental quantity in an atom which increases in regular steps with increasing atomic number. The corelation between X-rays spectra and atomic number indicated that an element is characterized by its atomic number and not by atomic mass.