John Dalton
Well, for me, the chemist who marked me the most is John Dalton, since he laid the foundations of modern chemistry. Dalton is a British chemist, mathematician and meteorologist who was born on September 6, 1766. He was the one who proposed the theory that all substances are made of atoms and that the atoms of each element are identical and also held that chemical compounds are the combination of atoms of different elements and in chemical reactions they rearrange and combine. Which literally is what all our current atomic models and theories are based on, it surprises me that in a time without any technological help only with imagination and experimental data he was able to come up with the basis of chemistry which for me at least is something very difficult to understand today with all the technology and chemical advances that have been made.