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?

Explanation

The nucleus of a hydrogen atom does not contain neutrons it contains only one proton and its mass is `1.67 xx 10^(-27) kg` and hence mass of hydrogen nucleus is `1.67 xx 10^(-27 )` kg. The a-particle nucleus is made up of 2 protons and 2 neutrons hence mass of nucleus of - particle is `= 4 xx 1.67xx 10^(-27) kg`
`=6.68xx10^(-27)kg`
Since the mass of the scattered a-particle is greater than the mass of nucleus of hydrogen atom, so it cannot be thrown back in head on collision but it will pass through the atom of hydrogen without deviating from its path. This is the case where a football collides with a tennis ball that is at rest.