Question

defects of Mendeleev periodic table what is meant by 8th group​

Answer 1

Explanation:

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. ...

Later on, isotopes of elements were found which violated Mendeleev's periodic law.

Answer 2

Answer:

1.the place of hydrogen is still undecided

2.some elements with have high atomic size and less atomic number are place after elements having high atomic number it causes problems

hope it helps...........

________________@divu