Limitations of the Rutherford Atomic Model

J.J Thomson discovered electrons through a pudding model. Later on, his discovery of the nature of the atom was studied by Rutherford. In the Rutherford atomic model, the alpha particles were bombarded into a gold sheet. The alpha particles were used intentionally to be able to track their trajectory when bombed into the gold sheet, which was earlier assumed to contain only electrons.

Upon observing the trajectories of the alpha particles, various conclusions were made about the structure of atoms. Rutherford proposed that electrons revolve around the nucleus in fixed paths called orbits. He also concluded that most of the space inside the atom is empty since most of the alpha particles get undeflected. The positive particles are accumulated in small spaces only as the alpha particles get deflected in small regions only. The electrons also spin in a circular fixed path known as the orbit. The Rutherford model cannot explain the arrangement of electrons in an atom.

Limitations of the Rutherford Model

Stability of the Atom

The Rutherford model was unable to describe the stability of the atom. However, it can describe the location of protons or positive charges at the centre of the atom. The stability of the atom was further described by the Bohr model of the atom on the concept of the energy associated with each orbital of the atom. Rutherford proposed that electrons revolve around the nucleus in fixed paths called orbits. The Rutherford atomic model explains the presence of a positive charge that stabilises the negative charge of the electrons inside the atom. 

The Bohr atomic model explains the energy of the electrons, while the Bohr orbit rule can help find the number of electrons available in each orbit. 

Electron position in the orbit

Rutherford proposed that electrons revolve around the nucleus in a fixed path called orbits.

The Rutherford atomic model did not explain the position and arrangement of the electrons in the atom’s orbit The model only concludes that positive particles are present inside the atom and does not mention the electrons’ position.

Niels Bohr well explained the number of electrons in each orbit by giving a formula 2n2where n is the principal quantum number of the electron. In case of first orbit, for n=1, the number of electrons in the first orbit will be 2. Similarly the number of electrons can be calculated for different orbits in the atom.

Centripetal force experienced by electron

The Rutherford atomic model cannot explain the centripetal force which is experienced by the electron while revolving in the orbit. Rutherford proposed that electrons revolve around the nucleus in fixed paths called orbits and assumed that the electrons are random in their orbits. The motion is nearly circular in which electrons revolve around the nucleus of the atom.

While revolving in a circular motion the object experiences a centripetal force. Therefore the electron must experience centripetal force and must fall into the nucleus at some time. This concept was not explained by the Rutherford atomic model. Also, while moving in circular motion, it must radiate some energy and at some point the energy of the electron must be equal to zero and at that time the electron will fall into the nucleus of the atom. 

Conclusion

The Rutherford atomic model was used to find the existence of positive charged particles inside the atom. Earlier, J.J THomson discovered the electrons but did not mention positive charged particles.

The Rutherford atomic model reveals that most of the space inside the atom is empty as most of the alpha particles get deflected when bombarded on the gold foil. The positive charge is concentrated over a specific region and on a small scale. Rutherford proposed that electrons revolve around the nucleus in fixed paths called orbits.

The Rutherford atomic model has limitations, including the instability of the atomic structure. The model cannot explain the stability of the atom. It also does not describe the position of the electrons in each orbit. It can neither tell the number of electrons available in each orbit nor explain the arrangement of electrons in an atom. The model also cannot explain the force experienced by the electron while revolving in a circular orbit around the nucleus of an atom.