## Single Regions?

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

Saleha_Mian_3E
Posts: 32
Joined: Fri Sep 28, 2018 12:25 am

### Single Regions?

I was looking through the notes and I wrote that single, double, and triple bonds are considered single regions of electron density in VSEPR model, but what does single regions mean in terms of electron density?

505095972
Posts: 69
Joined: Fri Sep 28, 2018 12:17 am

### Re: Single Regions?

Well a single bond has 2 electrons, so I would assume it means that. A double bond has 4 electrons, so that would be its electron density. But i'm not totally sure.

Ahmet_Dikyurt_3L
Posts: 35
Joined: Fri Sep 28, 2018 12:23 am

### Re: Single Regions?

Saleha_Mian_3E wrote:I was looking through the notes and I wrote that single, double, and triple bonds are considered single regions of electron density in VSEPR model, but what does single regions mean in terms of electron density?

I think a single region is just a bond (doesn't matter single, double, or triple bond) or a lone pair of electrons. The number of regions determine the shape and the bond angles. For example; 3 regions is a trigonal planar with 120 degree angle.

timschaeffer Dis 1J
Posts: 38
Joined: Fri Sep 28, 2018 12:18 am

### Re: Single Regions?

The concept that single, double, and triple bonds are all "single regions" of electron density just means that, when using the VSEPR notation, all individual bonds (whether they are single, double or triple) count as 1 "X" .

For example, a central atom attached to two other atoms by two single bonds would be denoted in VSEPR as "AX2" and would be linear.
If the same central atom were connected to two atoms by two triple bonds, then the VSEPR notation would still be "AX2" and the molecule would still be linear.

Hai-Lin Yeh 1J
Posts: 89
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 1 time

### Re: Single Regions?

What is meant by "single region" is that there is this one area where this bond is happening, whether it be a single, double, or triple bond. Like for example, if you have a double bond, it doesn't mean you have 2 regions were a bond is happening. It's only one region where two atoms are bonded together, except with a double bond instead of a single or triple.

Jovian Cheung 1K
Posts: 48
Joined: Fri Sep 28, 2018 12:16 am

### Re: Single Regions?

Are single regions = electron domains?

Since in high school, I learnt that each bond pair OR lone pair is classified as a single electron domain.

Many thanks! (Hope this isn't hijacking the thread, just hoping that it would add to the discussion!) :-)

KHuang1L
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

### Re: Single Regions?

You count the number of single regions of electron density to determine what molecular shape the molecule has. That means that single, double, and triple bonds are counted as just one region of electron density and count as one additional X.

Saleha_Mian_3E
Posts: 32
Joined: Fri Sep 28, 2018 12:25 am

### Re: Single Regions?

timschaeffer Dis 1J wrote:The concept that single, double, and triple bonds are all "single regions" of electron density just means that, when using the VSEPR notation, all individual bonds (whether they are single, double or triple) count as 1 "X" .

For example, a central atom attached to two other atoms by two single bonds would be denoted in VSEPR as "AX2" and would be linear.
If the same central atom were connected to two atoms by two triple bonds, then the VSEPR notation would still be "AX2" and the molecule would still be linear.

Thanks you this helped a lot, so electron density is related to the bonds of the atom.

Saleha_Mian_3E
Posts: 32
Joined: Fri Sep 28, 2018 12:25 am

### Re: Single Regions?

Jovian you're good! this actually helped and I believe some people already helped clear this up, because single regions are related to the electron domain like if it is using the VSEPR model, "AX2" and would be linear this means that either it could have double or single bonds because the regions of electron density are the same.