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7th edition 2E.1 mistake ?

Posted: Wed Nov 28, 2018 9:35 pm
by Henri_de_Guzman_3L
2E.1 part b gives you a bond angle of 180 degrees (linear shape) and asks whether around the central atom there: must be, may be, or cannot be one or more lone pairs.

I'm pretty sure the answer is cannot be one or more lone pairs. Isn't the only way you can have a 180 degree bond angle (linear shape) with only 2 bonds with atoms and no lone pair bonds? In other words of the VSEPR form AX2?

The answer key in the back gives "may have lone pairs" but if you add one pair of electrons or 2 pairs of electron on the central atom, it changes the shape to angular. Right?

Re: 7th edition 2E.1 mistake ?

Posted: Wed Nov 28, 2018 9:44 pm
by CateJensen3K
I was also confused by this problem. I think that you are correct, but I am not 100% sure. I would email a TA just to make sure.

Re: 7th edition 2E.1 mistake ?

Posted: Thu Nov 29, 2018 12:38 am
by Jasmin Argueta 1K
I'm also very confused. I thought adding any lone pairs would change the shape completely.

Re: 7th edition 2E.1 mistake ?

Posted: Thu Nov 29, 2018 12:52 am
by Dakota_Campbell_1C
The question doesn't specify how many lone pairs there can be on the central atom, it only says "one or more lone pairs". After doing some research online, apparently a AX2E3 molecule will give a bond angle of 180 degrees.

Re: 7th edition 2E.1 mistake ?

Posted: Thu Nov 29, 2018 11:08 am
by Nikki Bych 1I
I don't believe it's a mistake--if you have a electron geometry of trigonal bipyramidal, but 3 lone pairs, the molecular geometry will be linear.

Re: 7th edition 2E.1 mistake ?

Posted: Thu Nov 29, 2018 2:18 pm
by Sona Hakobyan 3J
If you look at AX2E3 in Figure 2E. 7 on page 113 you will see that it is possible to have a linear structure with 3 lone pairs.

Re: 7th edition 2E.1 mistake ?

Posted: Thu Nov 29, 2018 7:11 pm
by Henri_de_Guzman_3L
Got it! AX2E3 is linear with three equatorial lone pairs.