Mendeleev's periodic table Modern periodic table

Mendeleev's periodic table	Modern periodic table
i. In Mendeleev's periodic table, elements were arranged in an increasing order of atomic weight. ii. In Mendeleev's periodic table there were 8 groups. iii. In Mendeleev's periodic table isotopes of same elements were given different positions. iv. A correct position could not be assigned to hydrogen in the Mendeleev's periodic table.	i. In Modern periodic table, elements are arranged in an increasing order of atomic numbers. ii. In modern periodic table, there are 18 groups. iii. In Modern periodic table isotopes of same elements are given same positions. iv. Hydrogen has been placed at the top of group I in modern periodic table.