Rutherford's Planetary Model of the Atom. By 1911 the components of the atom had been discovered. The atom consisted of subatomic particles called protons and electrons. However, it was not clear how these protons and electrons were arranged within the atom. J.J. Thomson suggested the"plum pudding" model.
In his experiment,fast moving alpha particles were made to fall on thin gold foil.he selected gold foil bcz he wanted as thin layer of metal as [possible It was about 1000 atoms thick . He chose helium alpha particles bcz it is doubly charged and fast moving. 
1. most of the alpha particles passed straight through the gold foil.
2. Some were deflected by foil by small angles.
3. and one out of every 12000 particles appeared to rebound.
1.Most of the space inside the atom was empty bcz alpha particles passed through the gold foil.
2. very few particles were deflected indicating their positive charge of the atom occupies very little space.
3.A very small fraction of alpha particles were deflected by 180 degree. 
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