(Polar molecules, Non-polar molecules, etc.)
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becca_vandyke_4b wrote:I thought he said that we will not need to know bond angle. That we will be asked to draw the Lewis Structure and then name the shape.
I think he doesn't expect us to know the exact bond angle (like 107)' but we should know and write it as less than 109.5' for something like the trigonal pyramid shape.
Ethan Yi 4E wrote:so is the test only on the things we learned after the last midterm?
Hi! Dr. Lavelle posted this announcement on his website: "Test 3 covers: End of Bonding from 3.12 (6 Ed.) and from 2D (7 Ed.); and all of Molecular Shape and Structure (see Syllabus and Outlines for details)."
I think the comparative strength of ion-ion, ion-dipole, dipole-dipole, dipole-induced dipole, and dispersion interactions may also on the test. Also I remember there are specific factors affecting induced dipole-induced dipole forces.
Josceline 3J wrote:for test 3 should we go about to study (the book) chapter 4 on molecular structures and shapes or should we focus on studying what the lectures are about? Since the test is supposed to be similar to the homework problems.
Professor Lavelle often stresses that it is most helpful to do the homework problems to prepare for a test so I would do as many of them as you can and review lecture notes to be sure you understand key concepts.
I believe we will need to know the basic angles of the more common shapes, like a tetrahedral has angles of 109.5. I don't think he will make use memorize all bond angles when there are lone pairs involved. I just think that we need to know that a lone pair causes greater repulsion and the bond angle of the subsequent atoms will decrease.
DavidEcheverri3J wrote:Will we also need to know the degrees of the shapes?
Dana Wilks 3I wrote:Does this mean that the material covered in this past Monday's lecture won't be included?
No it as stated on Dr. Lavelle's website, the test will only cover 3.12-3.16, 6.4-6.5, and 4.1-4.7 which do not include Monday's lecture.
Sarah_Kang_3K wrote:Hi guys.
What do we need to know about Acids and Bases for Test 3?
Need to know what lewis acids and lewis bases are--lewis acids accept electrons and lewis bases donate electrons.
Last edited by Mukil_Pari_2I on Tue Nov 27, 2018 6:12 pm, edited 1 time in total.
Emily Li 4A wrote:DavidEcheverri3J wrote:Will we also need to know the degrees of the shapes?
I think it's very likely that we have to know them, but at least we can use simple math to find angles in most of the shapes.
I think it's helpful to know the molecular structure, electron structure, angles, and the way it looks.
Angela Grant 3G wrote:Ashley P 4I wrote:Does anyone have a trick to memorizing all these things?
I made a big chart to study off of, you can find one online if you just search up VSEPR geometries
Thank you so much! I ended up making flash cards as well.
A trick I found helpful is memorizing the VSEPR equations such as AX3E2 and knowing what shape corresponds to those equations because as soon as you drew the Lewis Structure you could conclude the VSEPR equation and therefore concluding the shape. This also helps with knowing the hybridization.
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