Which shapes to memorize

(Polar molecules, Non-polar molecules, etc.)

Moderators: Chem_Mod, Chem_Admin

Stacey Phan 2I
Posts: 103
Joined: Wed Sep 30, 2020 9:59 pm
Been upvoted: 1 time

Which shapes to memorize

Postby Stacey Phan 2I » Sat Nov 21, 2020 1:14 pm

I was wondering if someone could tell me all the shapes we should memorize with their description?

BrittneyMyint1D
Posts: 110
Joined: Wed Sep 30, 2020 9:59 pm
Been upvoted: 3 times

Re: Which shapes to memorize

Postby BrittneyMyint1D » Sat Nov 21, 2020 1:33 pm

I'm assuming it's all the shapes that Dr. Lavelle mentioned in the lectures:
- linear: central atom has 2 bonding pairs; 180 degree bond angle
- trigonal planar: central atom has 3 bonding pairs, 120 degree bond angles
- tetrahedral: central atom has 4 bonding pairs, 109.5 degree bond angle
- trigonal bipyramidal: central atom has 5 bonding pairs, trigonal bond angles 120 degrees and axial bond angles 90 and 180 degrees
- octahedral: central atom has 6 bonding pairs, bond angles are 90 and 180 degrees
- trigonal pyramidal: central atom has 3 bonding pairs and 1 lone pair (arranged tetrahedrally but 3/4 positions are occupied by atoms)
- bent/angular: central atom has 2 lone pairs and 2 bonding pairs
- seesaw: central atom has 4 bonding pairs and 1 lone pair
- square planar: central atom has 4 bonding pairs and 2 lone pairs

May have missed a couple of details but hope this helped!

KatarinaReid_3H
Posts: 179
Joined: Wed Sep 30, 2020 9:41 pm
Been upvoted: 4 times

Re: Which shapes to memorize

Postby KatarinaReid_3H » Sat Nov 21, 2020 2:29 pm

I would recommend googling a lookup table as well as there is sort of a pattern to the molecular shapes.
Electron groups: 2, Bonding Groups: 2, Lone Pairs: 0 = Linear

Electron groups: 3, Bonding Groups: 3, Lone Pairs: 0 = Trigonal Planar

Electron groups: 3, Bonding Groups: 2, Lone Pairs: 1 = Bent

Electron groups: 4, Bonding Groups: 4, Lone Pairs: 0 = Tetrahedral

Electron groups: 4, Bonding Groups: 3, Lone Pairs: 1 = Trigonal Pyramidal

Electron groups: 4, Bonding Groups: 2, Lone Pairs: 2 = Bent

Electron groups: 5, Bonding Groups: 5, Lone Pairs: 0 = Trigonal Bipyramidal

Electron groups: 5, Bonding Groups: 4, Lone Pairs: 1 = Seesaw

Electron groups: 5, Bonding Groups: 3, Lone Pairs: 2 = T-Shaped

Electron groups: 5, Bonding Groups: 2, Lone Pairs: 3 = Linear

Electron groups: 6, Bonding Groups: 6, Lone Pairs: 0 = Octahedral

Electron groups: 6, Bonding Groups: 5, Lone Pairs: 1 = Square Pyramidal

Electron groups: 6, Bonding Groups: 4, Lone Pairs: 2 = Square Planar

Inderpal Singh 2L
Posts: 147
Joined: Wed Sep 30, 2020 10:02 pm
Been upvoted: 2 times

Re: Which shapes to memorize

Postby Inderpal Singh 2L » Sat Nov 21, 2020 3:30 pm

Would we have to memorize the bond angles as well?

Mahika More 1H
Posts: 57
Joined: Wed Sep 30, 2020 9:34 pm
Been upvoted: 2 times

Re: Which shapes to memorize

Postby Mahika More 1H » Sat Nov 21, 2020 4:39 pm

Inderpal Singh 3B wrote:Would we have to memorize the bond angles as well?

I don't think we would have to memorize bond angles for each one but you should know the general idea about how each shape looks and be able to deduce from there what the values of the angles are around (for example 90 vs less than 90 degrees).

darchen3G
Posts: 107
Joined: Wed Sep 30, 2020 9:39 pm

Re: Which shapes to memorize

Postby darchen3G » Sat Nov 21, 2020 5:04 pm

Here is a good image from sapling that has the shapes
Image
If it won't load here's the link: https://i.imgur.com/HrydyqN.png

Mahnoor_Wani_1I
Posts: 123
Joined: Wed Sep 30, 2020 9:35 pm
Been upvoted: 3 times

Re: Which shapes to memorize

Postby Mahnoor_Wani_1I » Sat Nov 21, 2020 5:14 pm

If you are struggling with memorizing the molecular shapes, watch this video: https://www.youtube.com/watch?v=r2XmaiEC0Vw!

Stacey Phan 2I
Posts: 103
Joined: Wed Sep 30, 2020 9:59 pm
Been upvoted: 1 time

Re: Which shapes to memorize

Postby Stacey Phan 2I » Sat Nov 28, 2020 11:28 am

BrittneyMyint2C wrote:I'm assuming it's all the shapes that Dr. Lavelle mentioned in the lectures:
- linear: central atom has 2 bonding pairs; 180 degree bond angle
- trigonal planar: central atom has 3 bonding pairs, 120 degree bond angles
- tetrahedral: central atom has 4 bonding pairs, 109.5 degree bond angle
- trigonal bipyramidal: central atom has 5 bonding pairs, trigonal bond angles 120 degrees and axial bond angles 90 and 180 degrees
- octahedral: central atom has 6 bonding pairs, bond angles are 90 and 180 degrees
- trigonal pyramidal: central atom has 3 bonding pairs and 1 lone pair (arranged tetrahedrally but 3/4 positions are occupied by atoms)
- bent/angular: central atom has 2 lone pairs and 2 bonding pairs
- seesaw: central atom has 4 bonding pairs and 1 lone pair
- square planar: central atom has 4 bonding pairs and 2 lone pairs

May have missed a couple of details but hope this helped!


This is extremely helpful thank you!!

Stacey Phan 2I
Posts: 103
Joined: Wed Sep 30, 2020 9:59 pm
Been upvoted: 1 time

Re: Which shapes to memorize

Postby Stacey Phan 2I » Sat Nov 28, 2020 11:29 am

KatarinaReid_1B wrote:I would recommend googling a lookup table as well as there is sort of a pattern to the molecular shapes.
Electron groups: 2, Bonding Groups: 2, Lone Pairs: 0 = Linear

Electron groups: 3, Bonding Groups: 3, Lone Pairs: 0 = Trigonal Planar

Electron groups: 3, Bonding Groups: 2, Lone Pairs: 1 = Bent

Electron groups: 4, Bonding Groups: 4, Lone Pairs: 0 = Tetrahedral

Electron groups: 4, Bonding Groups: 3, Lone Pairs: 1 = Trigonal Pyramidal

Electron groups: 4, Bonding Groups: 2, Lone Pairs: 2 = Bent

Electron groups: 5, Bonding Groups: 5, Lone Pairs: 0 = Trigonal Bipyramidal

Electron groups: 5, Bonding Groups: 4, Lone Pairs: 1 = Seesaw

Electron groups: 5, Bonding Groups: 3, Lone Pairs: 2 = T-Shaped

Electron groups: 5, Bonding Groups: 2, Lone Pairs: 3 = Linear

Electron groups: 6, Bonding Groups: 6, Lone Pairs: 0 = Octahedral

Electron groups: 6, Bonding Groups: 5, Lone Pairs: 1 = Square Pyramidal

Electron groups: 6, Bonding Groups: 4, Lone Pairs: 2 = Square Planar


Thank you so much I will definitely be using this to study!

Anastasia Yulo 1C
Posts: 90
Joined: Wed Sep 30, 2020 9:47 pm

Re: Which shapes to memorize

Postby Anastasia Yulo 1C » Sat Nov 28, 2020 12:04 pm

I studies the shapes that he shared on lecture and tried my best to understand them conceptually so that I could understand them:Trigonal Planar, tetrahedral, trigonal bipyramidal, octahedral, trigonal pyramidal, see-saw, square planar. Once I recognized the pattern in the repulsions, it helped me memorize the angles characteristic to each shape. This table is an extremely helpful, organized visual: https://data.templateroller.com/pdf_doc ... nt_big.png

Madison Muggeo 3H
Posts: 95
Joined: Wed Sep 30, 2020 9:35 pm

Re: Which shapes to memorize

Postby Madison Muggeo 3H » Sat Nov 28, 2020 2:58 pm

https://d20ohkaloyme4g.cloudfront.net/i ... 0_1697.png
Is the table that I memorized, it is really useful.

Kaitlyn Hernandez 3I
Posts: 133
Joined: Wed Sep 30, 2020 9:37 pm
Been upvoted: 2 times

Re: Which shapes to memorize

Postby Kaitlyn Hernandez 3I » Sat Nov 28, 2020 3:52 pm

Here's another helpful document that I've been using to help me study molecular shape!

https://www.angelo.edu/faculty/kboudrea ... _VSEPR.pdf


Return to “Determining Molecular Shape (VSEPR)”

Who is online

Users browsing this forum: No registered users and 2 guests