Question

What are the limitations of Mendeleev’s Periodic table?

Answer 1

1. Elements with large differences in properties were included in the same group. eg. Hard metals like copper (Cu), Silver (Ag) were included along with soft metals like sodium (Na), potassium (K),
2. No proper position could be given to the element hydrogen. Non-metallic hydrogen was placed along with metals like sodium (Na) and potassium (K).
3. The increasing order of atomic mass was not strictly followed throughout. eg. Co and Ni, Te and I
4. As isotopes are atoms of the same element having different atomic masses, they should have been given different positions while arranging them in the order of atomic mass. But this was not done.