13 3  SIZE OF THE NUCLEUS
As we have seen in Chapter 12, Rutherford was the pioneer who
postulated and established the existence of the atomic nucleus At
Rutherford’s suggestion, Geiger and Marsden performed their classic
experiment: on the scattering of a-particles from thin gold foils Their
experiments revealed that the distance of closest approach to a gold
nucleus of an a-particle of kinetic energy 5