Dalton's atomic model states that all atoms of a given element are identical in mass and properties. Is this a correct statement now? How is this postulate of Dalton's theory related to isotopes?

Assignment directions: pick one of the following chemists and perform a bit of research on him/her. answer the following questions. alice hamilton             rosalind franklin marie curie             gertrude b. elion ada yonath             henry cavendish robert boyle             antoine lavoisier mario j. molina             svante arrhenius