Rutherford performed 'Gold Foil' experiment to understand how negative and positive charges could coexist in an atom.He bombarded alpha particles on a 0.00004 cm thick gold foil.Alpha particles are emitted by radioactive elements like radium and polonium.These are actually helium nuclei (He2+).They can penetrate through matter to some extent.
He observed the effects of a-particles on a photographic plate or a screen coated with zinc sulphide as shown.He proved that the 'plum-pudding' model of the atom was not correct.
He observed the effects of a-particles on a photographic plate or a screen coated with zinc sulphide as shown.He proved that the 'plum-pudding' model of the atom was not correct.

*Observation made by Rutherford as following
1.Almost all the particles passed through the foil un-deflected.
2.Out of 20000 particles, only a few were deflected at fairly large angles and very few bounced back on hitting the gold foil.
*Results of the experiment
Rutherford proposed model for an atom and concluded following results:
1.Since most of the particles passed through the foil un-deflected. therefore most of the volume occupied by an atom is empty.
2.The deflection of a few particles proved that there is a 'center of positive charges' in an atom, which is called 'nucleus' of an atom.
3.The complete re bounce of a few particles show that the nucleus is very dense and hard.
4.Since a few particles were deflected it shows that the size of the nucleus is very small as compared to the total volume of an atom.
5.The electron revolve around the nucleus.
6.An atom as a whole is neutral, therefore the number of electrons in an atom is equal to the number of protons.
7.Except electrons, all other fundamental particles that lie within the nucleus, are known as nucleons.
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