Where do elements get their names?
Solution : The above figure shows the plum-pudding model proposed by J. J. Thomson. He described that .the atom consists of a uniform positive sphere of matter in which the mass is evenly distributed and in which the electrons are embedded like raisins in a pudding or seeds in a watermelon. This model was named as plum-pudding model, named after a traditional English dessert. Ernest Rutherford and Ernest Marsden proved this model wrong using -Scattering experiment which also led to discovery of positive particles (p rotons) and neutral particles (neutrons) in the nucleus. When an unknown particle is caused to move between two electrically charged plates, its path is deflected by a smaller magnitude in the opposite direction from that of a beta particle. The conclusion about the charge and mass of this unknown particle is as follows : 1. Since the unknown particle is deflected in the opposite direction from that of beta particles (negatively charged particle) we can conclude that, the unknown particle is positively charged and the charge on the unknown particle is opposite to beta particles, 2. It’s said that the unknown particle is deflected by smaller magnitude than the beta particle which means the unknown particle is heavie r than beta particle. Therefore , we could conclude from the above observations that the unknown particle is positively charged and heavier than beta particle.