State three points of difference between Mendeleev’s Periodic Table and Modern Periodic Table.
Mendeleev's Periodic Table - 1. It is based on atomic mass. 2. It has 8 groups and 7 periods. 3. No place for isotopes. Modern Periodic Table- 1. It is based on atomic number. 2. It has 18 groups and 7 periods. 3. Isotopes have a place.
