Marie Curie conducted pioneering radioactivity research.
Marie Skłodowska Curie ( [ ˈkjʊri , _ kjʊˈriː ] [ kyʁi ] ; [ kʲiˈri ] ; 7 November 18674 July 1934 ) , born Maria Salomea Skłodowska ( [ ˈmarja salɔˈmɛa skwɔˈdɔfska ] ) , was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity . Her achievements included the development of the theory of radioactivity ( a term that she coined ) , techniques for isolating radioactive isotopes , and the discovery of two elements , polonium and radium .