Question

position of isotopes in the mendeleev's and modern periodic table?

Answer 1

Isotopes are atoms of the sameelement having different atomic mass but same atomic number. For e.g., there are three isotopesof hydrogen with atomic mass 1, 2, and 3. According to Mendeleev's periodic table these should be placed at three separate places.

Answer 2

Position of isotopes in the mendeleev's and the modern Periodic table

Isotopes were discovered long time after Mendeleev put forth the periodic table.

A challenge was posed in placing isotopes in Mendeleev's periodic table,as isotopes have same chemical properties but different atomic masses.

Later , the isotopes of Cl 17 - 35 and Cl 17 - 37 were placed in the same group as both have the same atomic numbers.

-@ Virat2003