Question

how did the modern periodic table solved the problem of placing of isotopes and hydrogen in the table

Answer 1

In the early time elements were arranged according to their atomic mass so it created the problem for isotopes. But in the modern periodic table elements were arranged according to their atomic number so it solved that problem. Hydrogen is placed sepratedly so the problem with hydrogen also gets solved.

Answer 2

Earlier The Basis Of Arranging Elements Was Atomic Mass Due To Which Scientists faced Problem assigning a fixed place to isotopes , but after the Discovery By Lother And Mayer , Atomic Number Became the basis of classification and isotopes got A fixed place