Henri Becquerel and the Discovery of Radioactivity

Ultraviolet light has a higher frequency (and a shorter wavelength) than visible light does. Higher frequency also means higher energy. 

X-rays have a higher frequency and energy than ultraviolet light does. 

Gamma rays have an even higher energy than X-rays do. Gamma rays are the most dangerous form of radiation. 

Becquerel and the Curies concluded that the rays emanated from within the uranium itself. This result suggested that uranium atoms are not Uttle, indestructible, hard spheres (as Dalton had suggested), but that they can in some way emit particles. In particular, they identified one kind of particle as having a negative charge. The notion that atoms have structure to them was born. It was Marie, in fact, who coined the term radioactivity to describe this phenomenon. For their work, Becquerel and the Curies shared the 1903 Nobel Prize in physics. 

Pierre and Marie Curie shared the 1903 Nobel Prize in physics for their work explaining radioactivity that occurs naturally. Their daughter, Irene Joliot-Curie (1897-1956), and Irene s husband, Jean-Frederic Joliot-Curie (1900-1958), shared the 1935 Nobel Prize in chemistry for their discovery of radioactivity that can be induced artificially. 

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