In Rutherford's experiment, generally the thin foil of heavy atoms



In Rutherford’s experiment, generally the thin foil of heavy atoms, like gold, platinum, etc., have been used to be bombarded by the a -particles. If the thin foil of light atoms like aluminium, etc., is used, what difference would be observed from the above results?


Heavy atoms such as gold, platinum have heavy nucleus. Heavy nucleus contains large amount of positive charge. When a beam of a ∝ -particles is shot at a thin gold foil, most of them pass through without much effect.
Some however, are deflected back or by small angles due to enormous repulsive force of heavy nucleus. If light aluminium foil is used, the number of ∝-particles deflected back or those deflected by small angles will be negligible.