How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?

Explanation

With the adoption of atomic number as the basis of classification of elements, some of the anomalies in the Mendeleev.s Periodic Table now disappear. These are:
(i) Position of hydrogen: The atomic number of hydrogen is 1 and hence, it should occupy the first position in group 1 of the Periodic Table. But, because of its chemical similarity with elements of group 1 and group 17, the position of hydrogen in the Periodic Table is still debated.
(ii) Position of isotopes: As the isotopes of an element have the same atomic number, they should occupy the same place in the Periodic Table.
(iii) Position of anomalous pair: The position of anomalous pair of elements, i.e., pair of elements in which the element with higher atomic mass precedes the clement with lower atomic mass is also decided. When these elements are arranged in order of their atomic numbers, they occupy their natural places in the Periodic Table as shown in following table.