## Bond angles

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

Deepika Pugalenthi 1A
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

### Bond angles

For bond angles, do we only have to know 120 degrees and 109.5 degrees? Is there any formula as to how to determine these bond angles?

Aili Ye 4L
Posts: 58
Joined: Fri Sep 28, 2018 12:16 am

### Re: Bond angles

I may be wrong, but we do not need to know any formulas. The angles we give should be approximate.

Kenan Kherallah 2C
Posts: 78
Joined: Fri Sep 28, 2018 12:17 am

### Re: Bond angles

Yes we do not need to memorize only know that AX4 is a tetrahedral and AX4E is trigonal pyramidal, etc

Jeremy Feng 1A
Posts: 30
Joined: Fri Sep 28, 2018 12:18 am

### Re: Bond angles

We are supposed to know the angles based on a rough guideline for each shape, but for certain cases, such as molecules with lone pair electrons, we are to estimate if the bond angle is greater than or less than the "standard" angle for the shape.

Jaifreen_Bhangu_3K
Posts: 34
Joined: Fri Sep 28, 2018 12:26 am

### Re: Bond angles

Yes, you don't need to know exact bond angles.

Mhun-Jeong Isaac Lee 1B
Posts: 54
Joined: Fri Sep 28, 2018 12:17 am

### Re: Bond angles

Reiterating an above response, for many of the shapes, lone electron pairs causes angles to decrease. In that instance, you only need to know that the angle is less than an established value. For example, for trigonal pyramidal, you just need to know that the angle is less than 109.5 degrees. You wouldn't have to know that it is actually 106 degrees.