Question

What is the basic difference between Mendeleev's periodic table and modern periodic table?

Answer 1

Mendeleev's Periodic Table	Modern Periodic Table
1.Mendeleev proposed this table which has 7 groups and 6 periods	1.Moseley proposed this table which has 18 groups and 7 periods
2. 63 elements were included in Mendeleev's periodic table.	2. 118 elements are present in Modern periodic table
2. This is arranged based on the increasing order of atomic mass of elements.	2.This is arranged based on the increasing order of atomic number of elements.
3.Mendeleev's periodic law: The physical and chemical properties of elements are the periodic functions of their atomic masses.	3.Modern periodic law: The physical and chemical properties of elements are the periodic functions of their atomic number.
4.In this table, there is some ambiguity in the arrangement of elements like anomalous pairs.	4.In this table, all the elements are arranged systematically and no anomalous pairs were formed.
5. Noble gases were not included in the table as they were not discovered at that time.	5. Noble gases were arranged in the 18th group as a separate group
6.Isotopes have to be given separate positions due to different masses but they were not given any position in the periodic table.	6. Isotopes are given same positions in the periodic table as they have same atomic number.
7. Transition elements are listed with other elements in Mendeleev's periodic chart.	7. Transition elements are represented in a separate block in the periodic chart of the Modern Periodic Table.