Marie hypothesized that radation doesn't come from the molecule, it comes from the atom. Marie Curie had a theory of radioactivity, that theory was that radioactivity broke down atoms, in return released radiation in energy and subatomic particles. She found this theory by doing different expirements.
Marie Curie also faced many struggles along with becoming a atomic scientist, she had a family along the way, thus she had to be a mother, and wife. She also had to be a nurse during WW1.