Thomson's Atomic Model

 

We have talked about Dalton's Atomic theory in our previous blog. According to his theory atom was invisible and indestructible. In our last blog, we talked about charged particles of matter, also known as fundamental particles. Discovery of these fundamental particles, electrons and protons, led to the failure of aspects of Dalton's atomic theory. After this failure, it was considered necessary to know that how the electrons and protons are arranged in atom. 

To explain this, many scientists proposed various atomic models. J.J. Thomson was the first to propose a model for the structure of an atom. In the March of 1904, Thomson published his model of the atom in "Philosophical Magazine" the leading British science journal of the day. He proposed that the model of an atom is similar to Christmas pudding. The electrons are in a sphere of positive charge like dry fruits in a spherical Christmas pudding. We can also think of an watermelon. While the electrons are studded in the positively charged sphere like the seeds in watermelon.

His basic proposal was:

• An atom consists of a positively charged sphere and the electrons are embedded in it. 

• The negative and positive charges are equal in magnitude. So, the atom as a whole is electrically neutral.

Although the Thomson's model explained that atoms are electrically neutral, but the results of experiments carried out by other scientists could not be explained by this model. We will talk about some of them in our upcoming blogs. Until then, try to figure out why this model of Thomson failed in the first place. We will answer this in out next blog.

Fore more details refer to Beyond Reaction: Fundamental Chemistry