Draw a labelled diagram for α-particle scattering experiment. Give Rutherford's observation and discuss the significance of this experiment.

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Alpha-particle experiment led rutherford to the discovery of atomic nicleus.  

 
Observations of the $\mathrm{\alpha }$ particle experiment. 

i) Most of the alpha particles pass straight through the gold foil. It means that they do not suffer any collision with the gold atoms.

ii) Only about 0.14 % of incident alpha particles are scattered by more than 1^o. 

iii) About 1 alpha particle in every 8000 alpha particles deflect by more than 90^o. 

Significance of rutherford's experiment:

His experiment led him to conclude that, the entire positive charge of the atom must be concentrated in a tiny central core of the atom. The tiny massive central core of the atom was named as the atomic nucleus.