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### bond angle

Posted: Mon Oct 31, 2016 7:25 pm
for our midterm, will we be asked to give the bond angle of each shape? if so, how do we calculate the bond angle or is it just something we have to memorize. thank you!

### Re: bond angle

Posted: Mon Oct 31, 2016 7:45 pm
To figure out bond angle just know the molecular shape. Like trigonal bipyramidal have angles of 120, 90, and 180. However, I'm pretty sure you don't need to know bond angles for the midterm however, it would be a good idea to know the names of the molecular shapes as they are in the coursereader chapter that Mr. Lavelle said was going to be on the midterm.

### Re: bond angle

Posted: Mon Oct 31, 2016 7:55 pm
Yes it would be a good idea to know the shapes of the bonds and there names. In terms of the calculating the bond angle, the degree of the angle often has to do with how many molecules are present but because the degree angle is not the same every shape, it is best to memorize the bond angle degree and associate it with the shape and the name of the bond.

### Re: bond angle

Posted: Mon Oct 31, 2016 8:21 pm
The bond angles are simply to memorize. However, they are generally very simple. Most structures have angles of 90, 120, or 180 degrees. The noted exceptions are bent 109.5 degrees, where there are three regions of electron density and one is filled by a lone pair. Another is bent 104.5 degrees, where there are four regions of electron density and two are filled by lone pairs. The third exception is trigonal pyramidal, where the angles are 107 degrees. And that's all!