Question

What is Rutherford's model of an atom and discuss it's shortcoming?

Answer 1

many ways, the Rutherford model of the atom is the classic model of the atom, even though it's no longer considered an accurate representation. Rutherford's model shows that an atom is mostly empty space, with electrons orbiting a fixed, positively charged nucleus in set, predictable paths.


This model of an atom was developed by Ernest Rutherford, a New Zealand native working at the University of Manchester in England in the early 1900s. Rutherford spent most of his academic career researching aspects of radioactivity and, in 1908, won the Nobel Prize for his discoveries related to radioactivity. It was after this that Rutherford began developing his model of the atom.


Discovery of the Atom
The atom was first conceived of by the Greek philosopher Democritus in approximately 400 BCE. The concept was lost during the Dark Ages of Europe until 1803, when the British scientist John Dalton speculated that everything was composed of very tiny indivisible particles called atoms.

Dalton's simple model of an atom persisted until 1897, when another British physicist, J.J. Thomson, discovered that atoms contained tiny negatively charged particles called electrons. From 1897 to 1909, scientists thought that atoms were composed of electrons spread uniformly throughout a positively charged matrix. J.J. Thomson's model was known as the plum pudding model.


Dalton's model of the atom depicted a tiny, solid, indivisible sphere. Thomson's plum pudding model shows electrons (the green circles) distributed in a positively charged matrix.

Answer 2

1. The major features of the Rutherford atomic model are as follows.

All protons are present inside the nucleus, which is situated at the centre of the atom.Electrons reside outside the nucleus and revolve around the nucleus in well-defined orbits.The size of the nucleus is very small in comparison to the size of an atom. As per Rutherford’s calculations, the size of the nucleus is 105 times smaller than an atom.As the mass of the electron is negligible in comparison to the mass of the proton, almost all the mass of the atom is concentrated in the nucleus.

2. Drawbacks of Rutherford’s model are listed below:

 

Rutherford’s model failed to explain stability of atoms. According to Rutherford’s model, electrons are revolving around the nucleus. This means, electrons would be in a state of acceleration all the time. Since electrons are charged particles, therefore, electron revolving in a circular orbit should continuously emit energy. It is because whenever a charged particle is accelerated it emits energy. As a result of this, revolving electron would lose energy and would slow down. So, it would no longer be able to resist the attractive force of the nucleus. Hence, it would move closer and closer to the nucleus and would finally fall into the nucleus by following a circular path. This means atom should collapse but actually we know atom is stable.Rutherford’s model does not explain the distribution of electrons around the nucleus.Rutherford’s model does not tell anything about the energy of electrons.