Rutherford in 1911, gave a new picture of atomic structure by performing an alpha scattering experiment and he also propose the existence of a nucleus within the atom.
Experimental setup
In order to propose the structure of an atom, Rutherford performed an experiment known as the alpha scattering experiment or gold foil experiment
In this experiment, he bombarded the narrow beams of alpha particles from a radioactive source into a sheet of gold foil.
The emergent beams of alpha particles were then allowed to fall on a spherical screen that is coated with .
Observation
Most of the alpha particles pass through the gold foil without any deflection.
A few alpha particles deflected through minimal angles and few were deflected at large angles.
A very small fraction of alpha particles get bounced back.
Conclusion
There is sufficient empty space within the atom as most of the alpha particles are passed through the gold foil without any deflection.
There are some alpha particles that were deflected through small angles and some of them deflected at a very large angle. This has happened because there is something that is contained within the atom having a positive charge and it should be placed at its center. This positively charged body of an atom is called the nucleus.
A very few alpha particles were bounced back, indicating that a direct hit of positively charged alpha particles to the positively charged nucleus in an atom.
Since the number of alpha particles that were deflected back or bounced back is very very small, he was suggesting that the size of the nucleus is very small as compared to the size of the atom.
