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Linear VSEPR model

Posted: Wed Nov 13, 2019 1:56 pm
by Marni Kahn 1A
I know that when the central atom has only two bonding pairs as far as possible, forming an 180 degree angle, it is considered to be a linear shape, but what if the central atom has lone pairs in addition to the two bonds?

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 1:59 pm
by Kate Osborne 1H
If the central atom has either zero or three non bonding electron domains in addition to the two bonding it is linear but any other number would be some other shape.

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 2:00 pm
by Katherine Chhen 3I
So the number of lone pairs can also determine the molecular shape of a molecule?

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 2:01 pm
by Kate Osborne 1H
In lecture Dr. Lavelle only went over examples where there are no lone pairs, but yes lone pairs do influence shape and I believe we will learn about it on Friday during lecture.

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 2:03 pm
by SGonzales_3L
Kate Osborne 1B wrote:If the central atom has either zero or three non bonding electron domains in addition to the two bonding it is linear but any other number would be some other shape.

Yes, we haven't learned it yet, but lone pairs also influence the shape of molecules due to electron-electron repulsions. In the book, it is discussed in section 2E.2, so I think we'll learn it very soon.

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 2:26 pm
by Diana Chavez-Carrillo 2L
Katherine Chhen 3I wrote:So the number of lone pairs can also determine the molecular shape of a molecule?

Yes, lone pairs can influence the molecular shape of a molecule but as mentioned by the previous responses we have not gone over it yet. However, to have an idea of some examples I provided an image below that shows you some shapes with lone pairs. I think it would be good to just see them and have an idea of how they look so when Lavelle does go over it you have some idea of how the shapes with lone pairs look like. Hope that helps :)

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 5:38 pm
by Callum Guo 1H
Lone pairs on the central atom adds a domain onto the central atom so it would not be linear. For example if you had H2O, the electron geometry would be tetrahedral because of 2 O-H bonds and 2 lone pairs.

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 5:39 pm
by KBELTRAMI_1E
Marni Kahn 3E wrote:I know that when the central atom has only two bonding pairs as far as possible, forming an 180 degree angle, it is considered to be a linear shape, but what if the central atom has lone pairs in addition to the two bonds?


I was also confused about this in the homework, I think it depends on the angle? not sure

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 5:40 pm
by KBELTRAMI_1E
Diana Chavez-Carrillo 3J wrote:
Katherine Chhen 3I wrote:So the number of lone pairs can also determine the molecular shape of a molecule?

Yes, lone pairs can influence the molecular shape of a molecule but as mentioned by the previous responses we have not gone over it yet. However, to have an idea of some examples I provided an image below that shows you some shapes with lone pairs. I think it would be good to just see them and have an idea of how they look so when Lavelle does go over it you have some idea of how the shapes with lone pairs look like. Hope that helps :)


wait so for the photo what would 1 lone pair look like for the first row

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 5:43 pm
by Minh Ngo 4G
The lone pair does affect the shape because of the repulsion so it pushes the two bonds downward more. The shape wouldn’t be linear since the angle is no longer 180.

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 7:11 pm
by Diana Chavez-Carrillo 2L
KBELTRAMI_4I wrote:
Diana Chavez-Carrillo 3J wrote:
Katherine Chhen 3I wrote:So the number of lone pairs can also determine the molecular shape of a molecule?

Yes, lone pairs can influence the molecular shape of a molecule but as mentioned by the previous responses we have not gone over it yet. However, to have an idea of some examples I provided an image below that shows you some shapes with lone pairs. I think it would be good to just see them and have an idea of how they look so when Lavelle does go over it you have some idea of how the shapes with lone pairs look like. Hope that helps :)


wait so for the photo what would 1 lone pair look like for the first row


If you have two atoms attached to the central atom and have 1 lone pair then it would be bent. But if you have only one atom attached to the central atom and 1 lone pair then it would be linear. Here is another chart-like image that I think can help you out more when it comes to lone pairs. That's how I've come to understand it but if I am wrong please correct me.

Re: Linear VSEPR model

Posted: Wed Nov 13, 2019 7:54 pm
by Nuoya Jiang
That would be a bent shape. I believe we'll talk about this in a few days.

Re: Linear VSEPR model

Posted: Thu Nov 28, 2019 9:56 am
by Katherine Chhen 3I
Ohh so only the number of atoms bound to the central atom determines the molecular shape.

Re: Linear VSEPR model

Posted: Thu Nov 28, 2019 12:03 pm
by emma brinton_3B
It varies depending on the atom of lone pairs. To be honest i would recommend memorizing the VSEPR formula and the shape. Linear models are AX2, AX2E3, and AX2E4.

Re: Linear VSEPR model

Posted: Thu Nov 28, 2019 3:48 pm
by Catherine Daye 1L
A molecule has a linear shape if it is bonded to 2 atoms and has no lone pairs, or bonded to 2 atoms and has 3 lone pairs.

Re: Linear VSEPR model

Posted: Sun Dec 01, 2019 11:56 pm
by Snigdha Uppu 1G
You determine VSEPR based on the regions of electron density, and lone pairs attached to the central atom are considered another region of electron density.

Re: Linear VSEPR model

Posted: Thu Dec 05, 2019 10:28 pm
by Kaitlynn Tran 3F
If it has 0, 3, or 4 lone pairs, the molecular shape will be linear. However, if it has 1 or 2 lone pairs, the molecular shape will be bent.

Re: Linear VSEPR model

Posted: Fri Dec 06, 2019 1:22 pm
by Katherine Chhen 3I
Kaitlynn Tran 3F wrote:If it has 0, 3, or 4 lone pairs, the molecular shape will be linear. However, if it has 1 or 2 lone pairs, the molecular shape will be bent.

Ohh okay, thank you!

Re: Linear VSEPR model

Posted: Sat Dec 07, 2019 11:33 pm
by ramiro_romero
it will create a bent molecular shape

Re: Linear VSEPR model

Posted: Sat Dec 07, 2019 11:38 pm
by Gwen Casillan Dis 1I
So if the central atom has lone pairs in addition to the bods, then the molecular shape will be bent due to the additional repulsion that the lone pairs have on the other atoms/bonded pair electrons.

Re: Linear VSEPR model

Posted: Sun Dec 08, 2019 6:44 pm
by Maika Ngoie 1B
If the molecule had 1 or 2 lone pairs it would then become bent. If it had 3, that would make it linear

Re: Linear VSEPR model

Posted: Sun Dec 08, 2019 7:02 pm
by Aarushi Solanki 4F
Lone pairs impact the bond angle due to lone pair-bonding pair repulsion, decreasing the angle.