A discussion on systematics of nuclear properties is presented. Mass, mass excess, and mass distribution within the nucleus is presented. The liquid drop model is described, with the nuclear parameters discussed. Trends related to magic numbers are introduced. Mass excess data are used to calculate energies in decays. Equations for determining nuclear radii are provided. Models that are used to describe the stability of nuclei are introduced. Nuclear shapes and structures are introduced. Spin, parity, and magnetic properties of the nucleus are discussed.
There was a lot of new stuff in this lecture but it was presented well.
ReplyDeleteThere was a lot of new stuff in this lecture but it was presented well.
ReplyDeleteVery informative, but I'll have to review it again to be able to achieve all of the objectives at the end of the lecture. Also, the Q value calculators didn't seem to like the method of positron decay presented in the lecture so I calculated that one by mass excess values.
ReplyDeleteThere is a bug in the program. I suggest you review the additional lecture on Q value calculator overview at: http://radchem.nevada.edu/classes/rfss/Lect%202%20nucl%20prop.html
DeleteI had never heard of the liquid drop model, but its form reminded me of the Van der Waals equation of state because it contains attractive and repulsive terms. I guess the equations aren't quite analogous but I found it interesting!
ReplyDeleteVan der Waals is terrific for describing water, a non-compressible fluid. The nucleons are basically non-compressible. You will see other comparisons to nuclear and chemical/electron properties in the class.
DeleteI enjoyed this lecture as well. The Q value information was presented clearly and I had no problems completing the quiz!
ReplyDeletegreat. For Quiz 1 on Friday you may find the other Q value calculator more helpful.
DeleteI was confused a bit for 1.1 on Quiz 2. The only stable isotope of As is As-75; however, all of the reasons in the dropbox are wrong. "odd-odd isotopes are stable near Z=33" is false since there are only 4 stable odd-odd isotopes (H2,Li6,B10,N14). "Only even-odd and odd-even isotopes are stable above Z=7" is wrong as there are tons of counterexamples e.g. Ne20 which is even even. Finally, the last one is wrong since a stable isotope of As does in fact exist...I was wondering how to go about answering this question.
ReplyDeletethanks for the comment. I should have written the question sharper. The question was to explore that odd-odd isotopes are generally not stable.
DeleteI should have written this more explicitly. Something like:
For odd Z elements, only isotopes with even neutron numbers can be stable. Since the The only realistic A the was odd (75) (odd + even = odd). That is what I was going for.
I understand the confusion and thanks for the comment.
Good to know the reason for the abundance of iron in the universe is due to its bonding qualities.
ReplyDeleteshows how nuclear properties can influence elemental abundance.
DeleteLecture was very informative and easy to follow. I found the examples after each topic very helpful. The quiz was simple.
ReplyDeleteThanks Dave. I am glad the examples were helpful.
DeleteI was confused a bit for 1.1 on Quiz 2. The only stable isotope of As is As-75; however, all of the reasons in the dropbox are wrong. "odd-odd isotopes are stable near Z=33" is false since there are only 4 stable odd-odd isotopes (H2,Li6,B10,N14). "Only even-odd and odd-even isotopes are stable above Z=7" is wrong as there are tons of counterexamples e.g. Ne20 which is even even. Finally, the last one is wrong since a stable isotope of As does in fact exist...I was wondering how to go about answering this question.
ReplyDeletesee comment above
ReplyDeleteGreat lecture/review and I loved the Q value examples, I love examples with numbers!
ReplyDeletethanks for the comment. Will keep the examples coming.
DeleteThe examples really helped me grasp the aspect of how to use the equations really helpful!
ReplyDeletethanks for the comment
DeleteThe answers to PDF Quiz 2 are now posted at: http://radchem.nevada.edu/classes/rfss/pdf%20quizzes.html
ReplyDeleteI had a question. In the liquid drop model, where can one find the pairing energy?
ReplyDeleteThe pairing term accounts for proton and neutron coupling. The exact term value depends upon if the nucleus is even-even, odd A, or odd-odd. An example can be found at: http://large.stanford.edu/courses/2011/ph241/chen1/
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