Failure of Rutherford’s Atomic Model

Ernest Rutherford conducted the alpha particle scattering experiment to understand the positioning of subatomic particles inside an atom. Depending on the outcomes of the alpha-particle scattering experiment, Rutherford’s atomic model provides information about the configuration of an atom. For instance, the model asserts that most of an atom is empty, with the nucleus containing the majority of the atomic mass. The Rutherford model improved on the Thomson model, but it still could not explain the stability of the atom or how the electron does not sink into the nucleus. Rutherford’s models of an atom include the nuclear model and the planetary model.

Rutherford’s Atomic Model

Rutherford organised the Alpha Particle Scattering Experiment to find out the arrangement of electrons in an atom. In Rutherford’s alpha scattering experiment, fast-moving alpha particles are emitted from the source, which is directed towards gold foil. After striking the foil, the path of the particles can be traced by flashes produced on the photographic plate. 

Experiment

• Rutherford organised the Alpha particle Scattering Experiment to investigate how electrons are grouped in an atom
• A thin sheet of gold was bombarded with rapidly moving alpha -particles
• He used the gold foil to provide an exceedingly thin coating
• The gold foil had a thickness of roughly 1000 atoms
• Alpha-particles are double-charged helium ions because they have a mass of around 4 amu, rapidly moving alpha-particles contain a lot of energy
• The notion was that the subatomic particles in gold atoms would deflect alpha particles
• Rutherford did not expect to see substantial deflections since the alpha-particles were much heavier than the protons
• However, the experiment yielded utterly unexpected outcomes

Observations

Rutherford discovered the following as a result of his α-particle scattering experiment:

• The vast majority of the fast-moving α-particles passed right through the gold foil
• Some of the α-particles were deflected by the foil at relatively small angles
• Only a few α-particles were redirected (by 180 degrees)

Inferences of the Experiment

• Because a vast number of the α-particles directed towards the gold sheet pass through it without deflection, the bulk of the space in an atom is empty
• Only a few α-particles deviated from their path, implying that the atom’s positive charge occupies a small amount of space
• Because only a tiny fraction of α-particles entirely rebounded, it suggested that the atom’s mass and positive charge are concentrated in a limited volume and are not evenly distributed

Failure of Rutherford’s Atomic Model

• According to Rutherford’s Model, electrons will circle the positively charged nucleus, which is not expected to be stable
• A charged particle travelling in a circular path would constantly lose energy and collapse into the nucleus
• This makes an atom unstable, even though atoms are incredibly stable
• The Rutherford Model could not answer the problem of atomic mass since it only theorised the existence of protons in the nucleus
•  It is unable to explain the electronic structure of atoms (No idea about the position and energy of e-)
• It could not explain the discontinuous spectrum

Other Name For Rutherford’s Atomic Model

Planetary Model of An Atom

• Rutherford claimed that an atom is essentially space with electrons circulating in predictable patterns around a fixed, positively charged nucleus
• Ernest Rutherford imagined the atom as a tiny solar system, with electrons orbiting a large nucleus and essentially space
• The nucleus filled just a tiny fraction of the atom
• When Rutherford suggested his model, which featured a nucleus made up entirely of protons, the neutron had not yet been identified

Nuclear Model of An Atom

• Rutherford concluded that all of the positive charge and the bulk of the mass of the atom must be contained in a tiny region in the atom’s interior, which he termed the nucleus
• The nucleus is the atom’s small, dense centre core, consisting of protons and neutrons
• The nuclear model evolved from Rutherford’s atomic model
• The protons and neutrons, which make up virtually all of the mass of the nuclear atom, are found in the nucleus, which is located in the atom’s heart
• The electrons are dispersed around the nucleus and take up most of the atom’s volume
• Rutherford concluded the presence of neutrons and thus paved the way for nuclear energy as we know it today

Conclusion

Rutherford’s experiment could not explain some phenomena. For example, Rutherford’s model could not account for atomic stability. According to Rutherford’s assumption, electrons circle at high speeds in a fixed orbit around the nucleus of an atom. In contrast, Maxwell explained that accelerated charged particles generate electromagnetic radiations. Electrons orbiting around the nucleus create electromagnetic radiation as a result. The electromagnetic radiation will carry the energy from the electrical motion, causing the orbits to gradually contract. Finally, the orbits in the nucleus of an atom compress and collapse. Consequently, Rutherford’s atomic model did not fit Maxwell’s theory and could not establish atomic stability.