Periodic Classification of Elements (C10)

Differentiate between the arrangement of elements in Mendeleev’s periodic table and Modern periodic table.

Answer

Mendeleev’s Periodic Table

  1. The elements were arranged according to increased atomic masses.
  2. Position of isotopes was not justified.
  3. Position of hydrogen was not justified because it resembles both with Alkali metals and Halogens.

Modern Periodic Table

  1. The elements were arranged according to increased atomic numbers.
  2. There was no problem in the placing of isotopes.
  3. Hydrogen has been given a unique position due to its resemblance with Alkali metals and Halogens.