What is the basic dierence in approach between Mendeleev’s Periodic Law and the Modern Periodic Law?

Question

What is the basic difference in approach between Mendeleev’s Periodic Law and the Modern Periodic Law?

Answer 1

Mendeleev Periodic Law states that the properties of the elements are a periodic function of their atomic weights whereas Modern Periodic Law states that the properties of elements are a periodic function of their atomic numbers. Thus, the basic difference in approach between Mendeleev’s Periodic Law and Modern Periodic Law is the change in basis of arrangements of elements from atomic weight to atomic number.