The first chemist featured in day 12 of our chemistry advent timeline essentially discovered a whole new group of chemical elements. Sir William Ramsay discovered five of the noble gases, winning a Nobel Prize in Chemistry for his work. Though he did also make some overoptimistic claims, as this Chemistry World article details!
Joseph John Thomson was a physicist who discovered the electron and formulated the ‘plum pudding’ model of the atom. Though this was superceded not too long after, it marked the first significant development in scientists’ model of the atom since John Dalton’s.
Marie Skłodowska Curie needs no introduction. Curie was the first woman to win a Nobel Prize – though the Physics prize in question was almost awarded to just her husband, Pierre Curie, and Henri Becquerel, until her husband wrote a letter to complain. She later went on to win a Nobel Prize in Chemistry and is still the only person to have won a Nobel Prize in two different sciences.
Other mentions to scientists who couldn’t be squeezed onto this one include Agnes Pockels, whose work laid the basis for surface science, and Lucy Boole, the first woman to co-author a pharmaceutical research paper and the first woman to be made a fellow of the Royal Society of Chemistry.