Rutherford Atomic Model:

The plum pudding model proposed by J. J. Thomson fails to explain some experimental data relating to atomic structure of elements. Ernest Rutherford, a British physicist, carried out an experiment and, based on the results, suggested the atomic structure of elements, coining the term “Rutherford Atomic Model.”

The Alpha Scattering Experiment by Rutherford

Rutherford conducted an experiment in which he attacked a thin sheet of gold foil with -particles and then examined the particle’s track after colliding with the gold foil.

Rutherford utilised a thin sheet of gold to focus high-energy -particle streams from a radioactive source in his experiment (100 nm thickness). He draped a bright zinc sulphide screen across the thin gold foil to examine the deflection generated by the -particles. Thomson’s atomic hypothesis was challenged in various ways by Rutherford’s observations.

Rutherford’s Alpha Scattering Experiment Results

Rutherford came to the following conclusions based on his observations:

• The majority of the space in one atom is vacant because a huge percentage of the -particles fired at the gold sheet crossed through it without being deflected.
• The gold sheet deflected some of the -particles at small angles, having caused the positive charge in each atom to be unequally distributed. The positive charge in an atom is confined to a small area of the atom.
• Only a few -particles were deflected back, meaning that only a few -particles had deflection angles approaching 180 degrees. As a result, positively charged particles in an atom take up very little space compared to the atom’s total volume.

Atomic Model of Rutherford

Based on the previous facts and conclusions, Rutherford proposed the atomic structure of elements:

• According to the Rutherford atomic model, positively charged particles and the majority of an atom’s mass were enclosed in a very small container. To describe this atom component, he developed the name “nucleus.”
• The nucleus of an atom is surrounded by negatively charged electrons, according to the Rutherford model. He also thought that the electrons that surround the nucleus travel in circular patterns at great speeds. To characterise these circular paths, he developed the term “orbits.” The nucleus is held together by a strong electrostatic force of attraction since electrons are negatively charged and the nucleus is a concentrated mass of positively charged particles.

Rutherford Atomic Model’s Limitations

Despite the fact that the Rutherford atomic model was founded on experimental findings, it was unable to explain certain phenomena.

• According to Rutherford, electrons orbit the nucleus along predetermined paths known as orbits. According to Maxwell, accelerating charged particles release electromagnetic radiation, thus an electron rotating around the nucleus should do the same. This radiation would carry the energy from the electron’s motion, but at the cost of orbital shrinkage.In the nucleus, the electrons would eventually collapse.
• Using the Rutherford model, an electron would disintegrate in the nucleus in less than 10-8 seconds, according to simulations. As a result, the Rutherford model was unable to explain atom stability and contradicted Maxwell’s hypothesis. One of the problems in Rutherford’s model was that he ignored the electron arrangement in an atom, leaving his theory incomplete.
• Early atomic models were incorrect and failed to explain certain experimental results, but they served as the foundation for future quantum mechanics advances.

Conclusion

The majority of the atom’s space is empty. That’s why, the majority of the -particles cross through the gold foil without deviating from their intended route. In the centre of the atom, there is a positive small component that deflects or repels the -particles.