Suppose you are given a chance to repeat the alpha-particle scattering experiment using a thin sheet of solid hydrogen in place of the gold foil. (Hydrogen is a solid at temperatures below 14 K.) What results do you expect?

Solution

The nucleus of a hydrogen atom is a proton of mass 1.67 × 10^–27 kg which has only about one-fourth of the mass of an alpha particle (6.64 × 10^–27 kg). Alpha particle is more massive and it won't bounce back in even a head-on collision with a proton. It is like a bowling ball colliding with a ping-pong ball at rest. Thus, there would be no large angle scattering in this case.

In Rutherford's experiment, by contrast, there was large-angle scattering because a gold nucleus is more massive than an alpha-particle. The analogy is there is a ping-pong ball hitting a bowling ball at rest.

Some More Questions From Wave Optics Chapter

An atom has a nearly continuous mass distribution in a ___ but has a highly non-uniform mass distribution in (Thomson's model/Rutherford's model)

The positively charged part of the atom possesses most of the mass in ___________ (Rutherford's model/both the models).