Introduction.
We are now brought face to face with the fundamental question, hardly touched upon at all in the previous part of this work, namely, that of the construction and mode of operation of the atomic mechanism itself. In the first place we must ask: What is the “architecture” of the atom, that is, what positions do the positive and negative particles take up with respect to each other, and how many are there of each kind? In the second place, of what sort are the processes which take place in an atom, and how can we make them interpret the physical and chemical properties of the elements? In this chapter we shall keep essentially to the first question, and consider especially the great contribution which Rutherford made in 1911 to its answer in his discovery of the positive atomic nucleus and in the development of what is known as the Rutherford atomic model or nuclear atom.