Drawbacks of Rutherford's Atomic Model
In Rutherford's Model of the Atom, Rutherford performed an experiment based on that experiment some of the hypotheses are given. At that time those hypotheses are considered revolutionary as there was an experiment to back that hypothesis. But as the experiment performed by Rutherford is rudimentary in nature, this model of the atom can be seen with a lot of major drawbacks, all of which we will be learning about under the heading Drawback
In this article, other than the Drawbacks of Rutherford's Atomic Model we will learn first learn about Rutherford's Atomic Model, and also we will compare this model to the modern-day model of the atom. So, let's start our learning of "Drawbacks of Rutherford's Atomic Model" in this article.
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Rutherford's Atomic Model
Many scientists came up with different ideas and explanations of the structure of an atom such as Thomsom and Bohr. The most classical and accurate model was introduced by the scientist named Ernest Rutherford in the year 1909. Rutherford's model later was said to be not the accurate version. However, the model did give a brief introduction to what and how the atom is formed. Rutherford explained that an atom is mainly made up of Electrons (negatively charged particles) and nuclei (positively charged particles), and they are arranged in the atom in a fixed manner.
According to Rutherford's model of an Atom, an atom is made up of mostly empty space and there exist electrons with spaces revolving around the nucleus in their fixed paths. The nucleus is positively charged due to the presence of protons (the positive charge), apart from the protons, neutrons (no charge on them) are also present inside the nucleus.
It can also be said that the electrons were embedded uniformly around the positively charged nucleus, and the force between the positive and the negative charges is what keeps an atom in place and intact.
Rutherford's Alpha-Scattering Experiment
The British physicist Ernest Rutherford conducted an experiment by bombarding alpha particles on a thin sheet made up of gold. As soon as the particles hit the gold foil, they gained certain trajectories, and the trajectories were studied by Rutherford. The gold sheet is extremely thin (around 100nm thickness) when met with the high energy beamed alpha particles, the sheet deflected the particles. It collided with the fluorescent Zinc Sulfate screen that was placed around the foil.
The image showing Rutherford's Alpha-Scattering Experiment is added below,
Note: To learn more about this experiment and more read Rutherford's Atomic Model.
Drawbacks of Rutherford's Atomic Model
The model of the atom proposed by Rutherford is still known as the classical model and was very much accepted at that time, however, later on, it was revealed that there were certain aspects that this model was not able to answer. Hence, there are certain drawbacks of Rutherford's model of an atom were introduced, they were as follows:
Inadequate Description of Electron Behavior
Rutherford did explain the revolving of electrons around the nucleus, however, the physicist did not mention how the electrons were placed inside, which ended up making Rutherford's model an incomplete model of the atom.
Failure to Explain Stability of Atoms
According to Maxwell, electrons should emit electromagnetic radiation as any accelerated charged particle has the tendency of emitting electromagnetic radiation. Rutherford also stated that the electrons do revolve around the nucleus in their orbits. Hence, due to the kinetic motion of the electrons, the radiation shall lead to the shrinking of the electrons in less than 10 seconds as the atom will keep on losing energy. Therefore, when Rutherford's model was mixed with Maxwell's theory, it was realized that the model is flawed.
Failure to Explain Atomic Spectra
Rutherford's model fails to explain the discrete emission and absorption spectra observed from different elements. It does not account for the specific wavelengths of light emitted or absorbed by atoms. The model does not provide a mechanism for the quantized energy levels of electrons, which are responsible for the spectral lines observed experimentally.
Limitations of Rutherford Atomic Model
If we compare, the modern-day model of the atom with Rutherford's model of the atom, we can see the following drawbacks other than the above-mentioned ones as well.
Lack of Explanation for Chemical Properties
As already discussed, we know Rutherford's model of the atom focuses on the structure of an atom but doesn't provide any further explanation of chemical properties or interactions between different elements. It also doesn't account for the formation of chemical bonds and the arrangement of electrons in different orbits.
Neglect of Electron Spin
In 1925, George Uhlenbeck and Samuel Goudsmit introduced the concept of electron spin, which is absent from Rutherford's model of the atom. They discovered that electron spin is the intrinsic property of electrons and has a significant influence on the behavior and properties of atoms.
Simplified Nature of the Nucleus
In Rutherford's model, the nucleus is simplified as a single positively charged particle, which is the source of all atomic mass. But as we know, this is an oversimplification of the nucleus as this neglects the existence of neutrons that are discovered later. Today, we know that neutrons and Protons contribute to the atomic mass and stability of the nuclei.
Lack of Subatomic Particles
At the time of Rutherford's model, electrons, protons, and neutrons are considered building blocks of the universe. But the discovery of subatomic particles such as muons, mesons, quarks, and other elementary particles disprove that. We can consider this as also a drawback of the Atomic model of Rutherford.
Check: Size of The Nucleus – Rutherford Gold Foil Experiment
Comparison of Rutherford's Model with Modern Atomic Models
The following table shows the comparison between Rutherford's Model with Modern Atomic Models.
Aspect | Rutherford's Model | Modern Atomic Models |
|---|---|---|
| Structure | Dense, positively charged nucleus at the center | Nucleus with protons and neutrons surrounded. by electron cloud |
| Electron Distribution | Electrons orbiting the nucleus like planets | Electrons distributed in energy levels or orbitals. |
| Size of the Atom | Mostly empty space | Mostly empty space |
| Stability of the Atom | Not well-explained | Explained by electron configurations and energy levels. |
| Electromagnetic Behavior | Neutral atom due to balanced charges | Neutral atom due to balanced charges |
| Explanation of Spectra | Explained the presence of alpha particles in gold foil experiment but failed to explain discrete line spectra | Explained by electron transitions between energy levels or orbitals |
| Subatomic Particles | Introduction of the proton and nucleus | Introduction of quarks and other elementary particles |
| Quantum Mechanics | Does not incorporate quantum mechanics | Incorporates quantum mechanics, wave-particle duality, and probability distributions |
| Experimental Evidence | Supported by the gold foil experiment | Supported by various experiments and observations. |
| Limitations | Failed to explain electron stability and spectra | Overcame the limitations of Rutherford's model and provided a more accurate description of atomic behavior. |
Also, Read
Sample Questions on Drawbacks of Rutherford's Atomic Model
Question 1: Why gold was used as a thin sheet in Rutherford's alpha scattering experiment?
Answer:
Since Gold has the best malleable property as a conductor, it could easily be formed into the thinnest sheet in order to observe an atom and its structure.
Question 2: Explain the particle used in the experiment done by Rutherford.
Answer:
The particle used was Alpha particles, denoted as "α" and alpha particles have 4 units of mass and 2 units of positive charge present on them. They are emitted from materials like Radium that are radioactive in nature. They can easily penetrate through objects, and since, atom has concentrated positive charge, they were able to deflect.
Question 3: Most of the atom is empty spaces. How was this statement concluded?
Answer:
When alpha particles were bombarded on the gold sheet, it was observed that most of the alpha particles went straight without any kind of deflection. This proved that most of the space in an atom is empty.
Question 4: What was one accuracy in Rutherford's model of an atom?
Answer:
The accuracy in Rutherford's model was regarding the position of the protons and facts about nucleus. Rutherford concluded that the protons are concentrated in a very small volume in the atom along with the neutrons and this small volume is known a nucleus.
