In a replication of the Geiger–Marsden scattering experiment, a collimated beam of alpha particles is directed at an ultra-thin sheet of platinum foil.
The vast majority of the alpha particles pass directly through the foil with absolutely no deviation from their original path. State what this observation reveals about the spatial structure of an atom.
A minute fraction of the alpha particles are deflected back towards the source, experiencing deflection angles of more than 90∘90^\circ90∘. Explain how the nature of this deflection demonstrates that the platinum nucleus must possess a positive electrical charge.
