The advantages of Modern periodic table over Mendeleev’s periodic table are :
1. Modern periodic table is based on the most fundamental property, the atomic number of elements, while Mendeleev’s periodic table is based upon the atomic masses of elements.
2. Modern periodic table explains clearly why elements in a group display similar properties. It also explains why elements of a group differ in properties from the elements of other groups.
In the modern periodic table, elements are arranged in accordance with their electronic configurations. The elements having similar electronic configurations are placed in the same group. Hence, elements in given group show similar properties. Elements with different electronic configurations are grouped separately, hence they show different properties.
Mendeleev’s periodic table does not provide any reason for the similarity and the difference in properties of elements.
3. Modern periodic table gives a satisfactory explanation about the chemical periodicity in the properties of elements. The periodicity in properties arises due to periodicity in electronic configurations of elements. Since the electronic configurations of elements are repeated at regular intervals, the properties of elements are bound to do so.
Mendeleev’s periodic table does not assign any reason for the periodicity in properties of elements.
4. In Mendeleev’s periodic table there are several anomalies, e.g. the position of isotopes, wrong order of atomic masses of some elements etc. In the long form of the periodic table, these anomalies have been removed.
5. In the long form of the periodic table, elements have been clearly separated as normal elements, transition elements and noble gases. Metals and nonmetals are also separated. But in Mendeleev’s periodic table there is no such separation of different types of elements.
6. In the modern periodic table the subgroups A and B are clearly separate because the elements belonging to subgroup A differ in properties from those of elements belonging to subgroup B. In Mendeleev’s periodic table the two subgroups are kept together.
7. The long form of the periodic table is comparatively easy to remember.