Question

how many isotopes are there in modern periodic table??

Answer 1

Dear student!
Modern periodic table considers the atomic no. as more fundamental property and takes it as basis of classification. Since, isotopes have same atomic no. but different atomic masses, so they are placed in same group same period, or simply explained as the position of all isotopes for an element is same. Like, C-12,C-14 all isotopes are at the same position where the carbon is placed.So, isotopes have no separate place in modern periodic table.