Page 1 of 1

### Bond Angle of bent

Posted: Wed Nov 20, 2019 11:26 pm
Is the bond angle of bent 109.5 or 120? thanks in advance

### Re: Bond Angle of bent

Posted: Wed Nov 20, 2019 11:33 pm
Less than 120 degrees if the molecule has one lone pair, and less than 109.5 degrees it the molecule has two lone pairs.

### Re: Bond Angle of bent

Posted: Thu Nov 21, 2019 12:11 am
Also, if you're dealing with water, the shape is also bent but the bond angle would be 104 degrees due to the presence of 2 lone pairs, which pushes the bonded atoms even closer together, further reducing the bond angle.

### Re: Bond Angle of bent

Posted: Thu Nov 21, 2019 12:18 am
It's gonna be less than 109.5 degrees because of the lone pair.

### Re: Bond Angle of bent

Posted: Thu Nov 21, 2019 12:22 am
Sorry, I should've clarified: for AX2E2, the bond angle is going to be slightly less than 109.5 degrees, while AX2E is less than 120 degrees. Both VSEPR formula represents bent/angular shape.

### Re: Bond Angle of bent

Posted: Thu Nov 21, 2019 1:27 am
The way I always remember it is by determining the electron geometries by observing the molecule by its areas of election density. This means that if a molecule has two bonds and two lone pairs, the electron geometry is tetrahedral because it has four areas of electron concentration. If the molecule has three areas of electron density, with two bonds and one lone pair, then I would consider the electron geometry to be trigonal planer. We know that the shape of a tetrahedral has bond angles of 109.5, while for trigonal planer, the bond angles are 120. Because there are lone pairs, we know the shape of the molecules aren't tetrahedral and trigonal planer but bent for both molecules, which means that the bond angles for the respective molecules are less than 109.5 and 120. Hopefully that makes sense.

### Re: Bond Angle of bent

Posted: Thu Nov 21, 2019 10:21 am
Depends on the number of lone pairs. If it's two, then <109.5 and if it's one <120.

### Re: Bond Angle of bent

Posted: Thu Nov 21, 2019 10:23 am
Tetrahedral is 109.5, Trigonal planar is 106-107 so bent would be a little lesser than the latter, being about 102-105 -- which is not something you necessarily need to know.

### Re: Bond Angle of bent

Posted: Thu Nov 21, 2019 2:14 pm
The bond angle of bent should be about 104.5 degrees.

### Re: Bond Angle of bent

Posted: Thu Nov 21, 2019 6:57 pm
If there are 2 lone pairs, then it would be less than 109.5 degrees. If there is 1 lone pair, then it would be less than 120 degrees. Both are bent shape, but the bond angles differ depending on the amount of lone pairs.

### Re: Bond Angle of bent

Posted: Fri Nov 22, 2019 8:55 am
If there are 2 lone pairs, then it would be less than 109.5 degrees. If there is 1 lone pair, then it would be less than 120 degrees. Bent shape simply means that there are lone pairs that create a repulsion that allows the bonds to come closer together, allowing for the angles to decrease.

### Re: Bond Angle of bent

Posted: Fri Nov 22, 2019 5:36 pm
It really depends on how many lone pair the molecule have. If there is only one lone pair, then the angle will be slightly-less-than 120 degrees, if there are two lone pairs, then the angle will be slighty-less-than 109.5 degrees.

### Re: Bond Angle of bent

Posted: Fri Nov 22, 2019 6:37 pm
But doesn't it depend on the lone pears that the molecule has which gives its shape.

### Re: Bond Angle of bent

Posted: Sun Nov 24, 2019 10:49 am
Always start by thinking of the entire electron configuration first! Much easier than memorizing different VSEPR combinations.

### Re: Bond Angle of bent

Posted: Sun Nov 24, 2019 12:07 pm
look at it as a trigonal planar shape with a lone pair instead of an atom, therefore, making a bond of less than 120 degrees.

### Re: Bond Angle of bent

Posted: Sun Nov 24, 2019 12:57 pm
If a lone pair is present, the angle will be less than 109.5 degrees because the electrons will repel the molecules away from it.

### Re: Bond Angle of bent

Posted: Sun Nov 24, 2019 1:02 pm
This depends on whether the atom has one or two lone pairs, in addition to its two bond pairs. If it has one lone pair, the bond angle will be < 120 degrees, however, if it has two lone pairs, it will have a bond angle << 109.5 degrees (ex. Water has a bond angle of approx. 104.5 degrees)

### Re: Bond Angle of bent

Posted: Sun Nov 24, 2019 1:39 pm
This depends on the vsepr formula of the molecule. there can be a bent shape in both AX2E2 and AX2E but the angles will be different in these two cases. In AX2E2 there will be more electron repulsion (its electron geometry is tetrahedral) so it will be slightly less than 109.5. In AX2E, the electron geometry is trigonal planar, and thus the bond angle will be slightly less than 120.