Question

Short note on position of isotopes in mendeleev’s and the modern periodic table?

Answer 1

•In mendeleev 's periodic table there was no place for isotopes.

•But in modern periodic table as the elements were arranged according to their atomic number. So there was no need to bother about isotopes.

Answer 2

In Mendeleev's periodic table ; there was a problem to place isotopes. Some of their positions are :
1. Chlorine : (Group 7 ; Period 3).
2. Carbon : (Group 4 ; Period 2)
.
.
In Modern Periodic table there is no isotopes present because it is depend on atomic number , not atomic mass