Exotic Nuclei

Abstract

Atomic nuclei are composed of two kinds of nucleons, the positively charged protons and the uncharged neutrons. Two forces are acting in nuclei; the attractive nuclear force between the neutrons and the repulsive electrostatic force between the protons. The number of protons in a nucleus is called its atomic number (symbol Z). The number also determines the number of electrons surrounding the nucleus and, hence, the chemical behavior of an atom; chemical elements differ in thei atomic number. The neutron number is indicated by N, and the mass number – that is, the total number of Z+n nuclear particles in a nucleus – by A. In light stable nuclei, protons and nuetrons are mixed in a ratio close to one-to-one as can be seen in the chart of nuclides (Figure 1). For example, the most abundant stable atomic nucleus of the element oxygen contains eight protons and eight neutrons (Z=N=8, A=16).