Question

Watermelon model was proposed by:

A. Rutherford

B. Thomson

C. Bohr

D. Sommerfield

Answer 1

Hint: To select the correct answer for this question we should know about different models of atoms that were proposed by different scientists.

Complete answer:

We should know that the Thomson atomic model was proposed by William Thomson in the year 1900. We should know that this model explained the description of an inner structure of the atom theoretically. This model gives us the idea of how a subatomic particle stays in an atom. It was strongly supported by Sir Joseph Thomson, who had discovered the electron earlier.

We should know that the Watermelon model was proposed after the discovery of a subatomic particle that is an electron. After the discovery of the sub-atomic particles of an atom scientists were eager to figure out the distribution of these particles within the atom. Several atomic models were proposed to explain the structure of the atom. However, a lot of them could not explain the stability of the atom.

Now, we will know about Thomson’s atomic model. We should note that, in 1898, J. J. Thomson proposed the first of many atomic models to come. He came with one model and states that an atom is shaped like a sphere. Where, the positive charge is uniformly distributed. The electrons are embedded in this sphere so as to give the most stable electrostatic arrangement.

We can understand this by taking an example of watermelon. If we cut a watermelon, we will see that there are seeds in it, and there is a red portion in it. The red portion that we eat is the embedded positive charge. And the seeds are electrons. That’s why we call it a Watermelon model.

Or, we 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 plum pudding model or the raisin pudding model.

So, in the above description we had successfully explained the watermelon model. And now we know that it was proposed by J.J Thomson. 

So, our correct answer is option (B).

Note: We should note an important aspect of this model, which is that it assumes that the mass of the atom is uniformly distributed over the atom. We should know that this atomic model of J.J Thomson atomic 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.