[3], An alpha particle is a sub-microscopic, positively charged particle of matter. [Rutherford was] a "tribal chief", as a student said. It is also known as the alpha scattering experiment.

(iii) What force or interaction is responsible for Rutherford scattering?



This puzzled Rutherford because he had thought that alpha particles were just too heavy to be deflected so strongly. s Geiger and Marsden didn't know what the positive charge of the nucleus of their metals were (they had only just discovered the nucleus existed at all), but they assumed it was proportional to the atomic weight, so they tested whether the scattering was proportional to the atomic weight squared. A 1908 paper by Geiger, On the Scattering of α-Particles by Matter,[14] describes the following experiment. *Please note: you may not see animations, interactions or images that are potentially on this page because you have not allowed Flash to run on S-cool. Reprinted with permission from Z. L. Liau et al.. Reprinted with permission from J. F. van der Veen, B. Pluis, and W. van der Gon, © 1990, Plenum Press. In this model the positive material is concentrated in a small but massive (lot of mass - not size) region called the nucleus. (2) The sign of the charge of the nuclei is the same as the sign of alpha particles. (iii) Nucleus contains neutrons and protons, and hence … The vacuum is important because any deflection of the alpha particles would only be because of collisions with the gold foil and not due to collisions with air particles. On changing the gas and electrode rod material. Most of the alpha particles did pass straight through the foil.

The conclusions of these experiments revealed how all matter on Earth is structured and thus affected every scientific and engineering discipline, making it one of the most pivotal scientific discoveries of all time. (1) There are neutrons inside the nucleus. Like most scientific models, Rutherford's atomic model was neither perfect nor complete. Construction of Alpha Scattering Experiment. (ii) Give two conclusions that can be deduced about the nucleus from the results of such an experiment. In an experiment where they shot a beam of alpha particles through hydrogen, the alpha particles knocked the hydrogen nuclei forwards in the direction of the beam, not backwards. They deduced this after measuring how an alpha particle beam is scattered when it strikes a thin metal foil. This model was devised by Lord Kelvin and further developed by J. J. Thomson. They noticed a few scintillations on the screen, because some alpha particles got around the plate by bouncing off air molecules.

So the alpha particle can …

Most of the α- particles passed straight through the foil without suffering any deflection. The nucleus was calculated to be about 1/10,000, Absorption and emission of ionising radiations - Eduqas, Home Economics: Food and Nutrition (CCEA). According to Thomson's model, if an alpha particle were to collide with an atom, it would just fly straight through, its path being deflected by at most a fraction of a degree. The neutron had not been discovered when Rutherford proposed his model, which had a nucleus consisting only of protons.