What are the effect of electrons on alpha particles during this experiment? Also why do we neglect them ?
4
-
1$\begingroup$ Possibly related to How did Rutherford conclude that most of the mass (as well as the positive charge) was concentrated in the nucleus? $\endgroup$– DiracologyCommented Aug 21, 2017 at 18:25
-
$\begingroup$ We neglect them because they have a trivial effect on scattering. Part is the reduced mass issue noted in one answer. Next is that the scattering happens at distances much smaller than the electron cloud. Then, there is the experimental fact that scattering with a +1 charged alpha is no different from scattering with a +2 ion. $\endgroup$– Jon CusterCommented Aug 21, 2017 at 18:42
-
$\begingroup$ @JonCuster Zero , etc. Does the previous question really address this OP's question regarding specifically the electron? I read it and it really doesn't appear to at least in terms of momentum, apart from charge. Size matters, but no mention of relative size in previous answer. $\endgroup$– docscienceCommented Aug 22, 2017 at 21:48
-
$\begingroup$ @docscience - it isn't clear to me how the OP thinks the electron might impact the scattering. That makes it hard to figure out what the OP is looking for. Bottom line, though, is that an electron or two will not change the scattering event at all. $\endgroup$– Jon CusterCommented Aug 22, 2017 at 23:53
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
The ratio between the mass of an electron and the mass of an alpha particle is on the order of 1/7300. And the ratio of the mass between a gold atom's nucleus and an alpha particle is about 200/1. So even though the speed of the electron might be faster than the speed of the gold nucleus it doesn't make up for the huge difference in mass and thus momentum.
Therefore between the two collisions, the alpha particle will 'bounce' back when colliding with a gold nucleus, but not with an electron.
answered Aug 21, 2017 at 18:29