In Rutherford’s experiment, generally the thin foil of heavy atoms, like gold, platinum etc. have been used to be bombarded by the α-particles. If the thin foil of light atoms like aluminium etc. is used, what difference would be observed from the above results?
In Rutherford's experiment, the deflection of positively charged -particles is caused by the enormous repulsive force from the concentrated positive charge in the nucleus. Heavy atoms like gold have a larger positive charge, resulting in significant deflections, where a very few -particles (~1 in 20,000) bounce back by nearly .
If a thin foil of light atoms like aluminium is used instead, the nucleus would contain a smaller positive charge. Consequently, the repulsive force experienced by the -particles would be reduced. As a result, the number of -particles deflected by small angles or bouncing back would be significantly smaller compared to the results observed with heavy atoms like gold.
Explanation
The context explains that the deflection and bouncing back of alpha particles in Rutherford's experiment is due to the enormous repulsive force from the concentrated positive charge in the nucleus. Heavy atoms have more positive charge, causing larger deflections. By logical extension within the provided concepts, using light atoms like aluminium, which have less positive charge, would result in a weaker repulsive force. Therefore, fewer alpha particles would be deflected by large angles or bounce back.