History of subatomic physics indestructible. But when the nucleus change its charge and/or mass (by emitting or capturing a particle), the atom can become the one of another element. Special relativity explained how the "mass defect" is related to the energy produced or consumed in reactions. The branch of physics that studies transformations and the structure of nuclei is now called nuclear physics, contrasted to atomic physics that studies the structure and properties of atoms ignoring most nuclear aspects. The development in the nascent quantum physics, such as Bohr model, led to the understanding of chemistry in terms of the arrangement of electrons in
Institute of Physics when the expansion of access to universities removed demand. In 1960, the Physical Society and the Institute of Physics merged, creating a single organization with the unwieldy name "The Institute of Physics and the Physical Society", which combined the learned society tradition of the Physical Society with the professional body tradition of the Institute of Physics. Under the leadership of Thomas E. Nevin an Irish branch of the Institute of Physics was formed in 1964. Upon being granted a royal charter in 1970, the organization was renamed as the Institute of Physics. There are four grades of membership: Associate Member,