How could the Modern Periodic Table remove various anomalies of Mendeleev's Periodic Table?

Explanation

The Modern Periodic Table removes all the anomalies and drawbacks of the Mendeleev's periodic table based on the increasing atomic mass by changing the basis of classification to atomic number. For example,
(a) All the isotopes of an element are now placed in the same position because they all have the same atomic number.
(b) The anomaly of higher atomic mass element being placed before the lower atomic mass element is removed when these elements are arranged in the order of increasing atomic numbers.