Differentiate between the arrangement of elements in Mendeleev’s periodic table and Modern periodic table.
Mendeleev’s Periodic Table
- The elements were arranged according to increased atomic masses.
- Position of isotopes was not justified.
- Position of hydrogen was not justified because it resembles both with Alkali metals and Halogens.
Modern Periodic Table
- The elements were arranged according to increased atomic numbers.
- There was no problem in the placing of isotopes.
- Hydrogen has been given a unique position due to its resemblance with Alkali metals and Halogens.