Question

Explain the difference between the distribution of positive charge in Thomson’s atomic model and Rutherford’s atomic model.

Answer 1

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.

Answer 2

Dear Student,

◆ 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...