Sir J.J Thomson was a British physicist and a Nobel laureate who discovered electrons and won the Nobel prize for the same. In the year 1903, Thomson proposed the atomic model theory, also known as plum pudding model or the watermelon model. In this model the atom is a spherical cloud in which the negatively charged electrons, positively charged protons and the neutral neutrons are floating around. It is also known as the plum pudding model, in which the atom acting as the pudding and the charged particles are taken in the context of the plums embedded in between the pudding. Although this model was very much well received by everyone back then, it still has some limitations with one being that it cannot explain the spectral lines of hydrogen atoms.