Nuclides with same
neutron number N but different atomic number Z, for example 198
80 Hg
and 197
79 Au , are called isotones 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