Question

Explain Demerits of Mendeelev periodic table.

Answer 1

Demerits of Mendeleev Periodic Table. He was unable to locate hydrogen in the periodic table. Increase in atomic mass was not regular while moving from one element to another. Hence, the number of elements yet to be discovered was not predictable.

Advantage of Mendeleev Periodic Table :-

1.He left blank Places which help scientist to discover new element

2.When Noble gasses was discovered Hel could add it to periodic table without any major changle  

3.He predicted the property of new element

Disadvantages :-

1. Couldn't explain position of Hydrogen  

2.Couldn't answer the question "Can we have an element with atomic mass 3 between Hydrogen and Helium  

3 He placed cobalt before Nickel though Cobalt has more mass

Hope u got the answer…

Answer 2

Demerits of Mendeleev periodic table is:
He placed some elements having higher atomic mass than a lower one like cobalt is placed before nickel.
position of hydrogen.
Only some elements were know at that time .