Question

WHICH OF THE POSTULATE OF DALTONS ATOMIC THEORY IS CHALLENGED BY THE NEXT GENERATION SCIENTIST ?

Answer 1

Following are the drawbacks of Dalton's Atomic theory which were challenged by the scientist:
1.with the discovery of subatomic particles: electron, proton and neutron  , the atom can no longer be considered as indivisible.
2. All atoms of same element are not perfectly identical at least they differ in their mass number. Such elements are called as Isotopes.
3. Atoms of dissimilar elements are not different eg : Isobars they have same mass numbers.