This edition: Atoms And Light: Exploring Atomic and Electronic Structure
As the the 20th century approached, scientists moved beyond the idea of the atom as indivisible by identifying its interior components: the electron (Thompson, 1897), the proton (Rutherford, 1920), and the neutron (Chadwick, 1932). The Bohr model (1913) of the atom added detail to the picture, describing how electrons jump between energy levels and emit distinct quanta of energy as they do. This led to the birth of modern subatomic theory. Today, by understanding the interactions of atoms with light, quantum theory can be applied in astrophysics or in forensic chemistry, where hand-held X-ray spectrometers read wavelengths of light to detect the presence of different materials.