Chapter 43 - NUCLEAR STRUCTURE AND NUCLEAR TECHNOLOGY

Abstract

This chapter introduces the basic neutron–proton model of the nucleus upon which modern nuclear models are based. It discusses the role that this model plays in 20th century physics and technology. The nucleus of the atom is a bound system of neutrons and protons that, collectively, are called nucleons. The binding energy of a nucleus is the minimum energy that must be added to a nucleus to separate it into its constituent neutrons and protons. As the number of protons in stable nuclei increases, the neutron number gets progressively larger than the proton number. In all nuclear reactions, the conservation laws involving energy, linear momentum, angular momentum, and charge apply. In a spontaneous disintegration of a nucleus, rest mass energy considerations require that the combined masses of the disintegration products be less than the mass of the disintegrating nucleus. The rest mass energy is transformed into kinetic energy, which is shared by the reaction products. Like the energies associated with an atom, the energies of a nucleus are discrete. A nucleus may absorb energy and make a transition to a state of higher energy. However, energy might be released and it might move to a lower energy state.