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Ch.2 - Atoms, Molecules & Ions

Chapter 2, Problem 92

Prior to Rutherford's gold foil experi-ment, the 'plum pudding' model of the atom represented atomic structure. In this model, the atom is composed of elec-trons interspersed within a positive cloud of charge. If this were the correct model of the atom, predict how the results of Rutherford's experiment would have been different. (a) The alpha particles would pass right through the gold foil with little to no deflection. (b) Most of the alpha particles would be deflected back toward the source. (c) Most of the alpha particles would be absorbed by the atom and neither pass through nor be deflected from the gold foil.

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Welcome back everyone. We're told that the plum pudding model of the atom predict the structure of an atom. In this model, the electrons are embedded plums in a positively charged pudding. If this is the accurate model of the atom, what would be the outcome of Rutherford's experiment? So recall that Rutherford is the scientists that had our gold foil experiment which we should recall led to our discovery of the small positively charged nucleus of an atom. So we want to go ahead and recognize that based on our diagram, we can see this positive charge that takes up a lot of space of this atom here, where we can see that this positive charge is very evenly distributed throughout our atom. And in our Rutherford gold failed experiment, we want to recall that Rutherford targeted alpha particles towards our atom of gold foil and some of these particles were deflected where others passed through. Being actually a majority of these alpha particles passed through our gold foil atoms. We want to recall that these alpha particles have a positive charge. Sorry, they have a positive charge. So it makes sense that as a majority of these alpha particles were aimed towards our gold foil, that a lot of them passed through and only a few became deflected. So we would confirm that the only correct choice as the outcome of Rutherford's experiment is that the alpha particles will travel straight through the gold foil with little to no deflection. So Choice B is going to be the correct choice to complete this example. As the given diagram? Definitely being an accurate model of the outcome or sorry, of the atom, which confirms the outcome of Rutherford's experiment, being that these alpha particles, which are positively charged, travel straight through the gold foil with little to no deflection. Because we do see that this atom or these atoms of gold foil have a very largely spread out positive charge throughout the atom. So B is our final answer. I hope everything I reviewed was clear. If you have any questions, leave them down below and I'll see everyone in the next practice video.