The model Atomic Thomson is a theory that talks about the structure of atoms was proposed by the British physicist Joseph Thomson, who is also the discoverer of the electron. Through this model, Thomson stated that the positively charged atom was made up of negative electrons, which were embedded in it, as if they were raisins in a pudding. It is because of this comparison that this atomic model is also known as " the raisin pudding model."
Thomson's model stated that electrons were uniformly distributed in the inner part of the atom, fixed in a positively charged cluster. The atom appeared as a sphere filled with positive charge, with electrons scattered like tiny granules.
Thomson's theory determined:
- The atom is made up of negative electrons, introduced into a positively charged balloon, just like a raisin pudding.
- Electrons are uniformly distributed within the atom.
- The atom is neutral, therefore, its negative charges are offset by positive charges.
The theory put forward by Thomson, although it favorably showed several of the observed events referring to chemistry and cathode rays, led to wrong predictions about the distribution of the positive charge within the atoms. These predictions were not compatible with the results produced by Rutherford's model, which proposed that the positive charge was condensed in a small area in the center of the atom, which would later be called the atomic nucleus.
Thomson's model was replaced by Rutherford's, when it was shown that it is not compact, but that it is totally empty, with the positive charge clustering in a small nucleus, surrounded by electrons.
