explain the difference between the distribution of positive charge in thomsons atomic model.
Answers
Answer:
Thomson’s Model of an Atom
All of us have seen a plum pudding and a watermelon in our daily life. Do you know one of the early models of an atom has been compared to a plum pudding, raisin pudding, and even a watermelon? The model we are talking about is the Thomson’s atomic model. Any idea why it has been given such names? Let us find out more about Thomson’s atomic model or Thomson’s Model of an Atom.
History
Before the discovery of subatomic particles, John Dalton came up with Dalton’s atomic theory where he suggested that atoms are indivisible particles. It explained atoms cannot be broken down into further smaller particles. However, the discovery of subatomic particles disapproved the postulates proposed in Dalton Atomic Theory.
The discovery of subatomic particles led to the search how the subatomic particles are arranged in an atom. J.J. Thomson was the first and one of the many scientists who proposed models for the structure of an atom. J.J. Thomson discovered negatively charged particles by cathode ray tube experiment in the year 1897.
The particles were named electrons. J.J Thomson believed electrons to be two thousand times lighter than a proton. He assumed that an atom is composed of a cloud of negative charge in a sphere of positive charges. J.J Thomson and Rutherford first demonstrated the ionization of air in x rays.
OR
Thomson’s Atomic Model
In 1898, J. J. Thomson proposed the first of many atomic models to come. He proposed that an atom is shaped like a sphere with a radius of approximately 10-10m, where the positive charge is uniformly distributed. The electrons are embedded in this sphere so as to give the most stable electrostatic arrangement.
Doesn’t the figure above remind you of a cut watermelon with seeds inside? Or, you can also think of it as a pudding with the electrons being the plum or the raisins in the pudding. Therefore, this model is also referred to as the watermelon model, the plum pudding model or the raisin pudding model.
An important aspect of this model is that it assumes that the mass of the atom is uniformly distributed over the atom. Thomson’s atomic model was successful in explaining the overall neutrality of the atom. However, its propositions were not consistent with the results of later experiments. In 1906, J. J. Thomson was awarded the Nobel Prize in physics for his theories and experiments on electricity conduction by gases.
Or
◆ Thomson's Plum-pudding model of atom -
According to this model, Atom consists of electrons embedded in sea of positive charge.
◆ Rutherford's Planetary model of atom -
According to this model, Atom consists of electrons revolve around heavy nucleus.
# Difference between the distribution of positive charge in Thomson’s atomic model and Rutherford’s atomic model -
According to Thomson, positive charge is uniformly distributed across the atom.
According to Rutherford, positive charge is concentrated in the central nucleus.
Thanks dear. Hope this helps you...