Who Is John Dalton

John Dalton was the first scientist to come up with an atomic theory, however there was a flaw in what he had initially believed. Dalton had a theory that atoms were indivisible and indestructible. J.J Thomson, also a scientist discovered electrons by using a cathode ray tube and showed the rays were negatively charged. Thomson recognized that Dalton’s accepted model of an atom did not consider particles being negatively or positively charged. Thomson then suggested a new model of the atom that was linked to plum pudding. The raisins in the pudding had represented the negative electrons and the positive charged electrons were shown through the dough. The electrons were believed to be on rotating rings throughout the atom. Thomson had abandon his other theory of “nebular atom” in which the atom was composed of immaterial vortices after using the new model. Although Thomson’s model of the atom proved some of the electrical properties of the atom due to electrons, the rest of the positively charged part of the atom was still ill-defined.

Thomson, Ernest Rutherford, later in 1911 proved his teachers plum pudding model as incorrect. Rutherford had hypothesised a very small nucleus of the atom contains a high positive charge. Rutherford used alpha particles, a positively charged nucleus of a helium-4 atom, at solid substances, like gold foil, to record the particle “strikes” against the fluorescent screen as they passed through the foil. Rutherford’s new model contained new features of high central charge concentrated into a small volume compared to the rest of the atom. The bulk of the atom’s mass is contained in the central volume later would be named the “nucleus.” Although, it was not expected for the alpha particles to pass through the foil unaffected, he saw a tiny amount of particles deflected at an angle and some ricocheted