The term "radioactivity" was "coined" by which of the following individuals?

The term "radioactivity" is associated with the groundbreaking work of Marie and Pierre Curie. They conducted extensive research on radioactive substances and are credited with isolating radioactive isotopes and understanding their properties. The concept of radioactivity was articulated after their studies on the phenomenon of spontaneous emission of particles and energy from certain elements, primarily focusing on radium and polonium, which they discovered.

Their pioneering efforts not only brought the term "radioactivity" into scientific nomenclature but also laid the foundation for further advancements in nuclear physics and medicine. The significance of their work in defining and expanding the concept of radioactivity made it a crucial milestone in the history of science.

The other individuals mentioned, while notable in their own rights, either contributed to different fields or were involved in related but distinct discoveries. Wilhelm Roentgen is known for discovering X-rays, Henri Becquerel for discovering radioactivity itself, and Henri Crookes for his work on cathode rays. However, it was the Curies who formalized the term and explored its implications in greater depth.