Question

How did Rutherford’s experiment change the model of structure of atoms?

Answer 1

After the failure of J.J Thomson plum pudding model of structure of atoms, Rutherford has given an experiment in which he explained about the model of structure of atoms. He conducted the experiment in which he used thin gold foil, radioactive elements and later noted the observations.

Complete step-by-step answer:
Rutherford conducted an experiment in which he bombarded the alpha particles to the thin sheet foil using radioactive sources. He noticed deflection created by the alpha particles. Around the gold foil, he fixed a fluorescent screen and noted observation:
-Large amount of alpha particles passed undeflected. This means that a large amount of space is vacant in the atom.
-He also observed that some alpha particles get deflected by small angles. This means that positive charge particles are present in small spaces.
-There are very few alpha particles that get deflected by ${{180}^{{}^\circ }}$ . This means that the presence of positive charge is very less in comparison to total atomic volume.

According to the observation, Rutherford gave a model of structure of atoms in which he stated that-
Positive charge particle is present in the centre of the atom which is known as nucleus.
-The negatively charged particles move in circular orbit around the nucleus.
-The negatively charged electrons and positively charged particles are held together by an electrostatic force of attraction.
-This is how Rutherford conducted the gold foil experiment

Note: There are many limitations of Rutherford model of structure of atoms-
Rutherford did not explain about the stability of an atom. He postulated that electrons move in circular orbit at a very high speed around the nucleus. Maxwell explained that the acceleration of charged particles will release electromagnetic radiations. The electromagnetic radiation will have energy from the motion of the particles as a result of which the orbit will shrink and collapse in the nucleus. He did not explain about the arrangement of electrons in the orbit.