TABLE OF CONTENTS The discoveries of radioactivity and isotopes were extraordinary advances. And as usual, they also raised new questions about the structure of atoms, questions that involved the atomic nucleus. We saw in Chapter 17 that the transformation rules of radioactivity could be understood in terms of the Rutherford-Bohr model of the atom. But that model said nothing about the nucleus other than that it is small, has charge and mass, and may emit an ? or a ? particle. This implies that the nucleus has a structure that changes when a radioactive process occurs. The question arose: Can a theory or model of the atomic nucleus be developed that will explain the facts of radioactivity and the existence of isotopes?
The answer to this question makes up much of nuclear physics. The problem of nuclear structure can be broken down into two questions:
What are the building blocks of which the nucleus is made?
How are the nuclear building blocks put together?
The attempt to solve the problem of nuclear structure, although still a frontier activity in physics today, has already led to many basic discoveries and to large-scale practical applications. It has also had important social and political consequences, stretching far beyond physics into the life of society in general, as this text has frequently noted in its earlier chapters.
The emission of ? and ? particles by radioactive nuclei suggested that a model of...
