7th edition 2E.1 mistake ?

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

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Henri_de_Guzman_3L
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

7th edition 2E.1 mistake ?

Postby Henri_de_Guzman_3L » Wed Nov 28, 2018 9:35 pm

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?

CateJensen3K
Posts: 32
Joined: Fri Sep 28, 2018 12:26 am

Re: 7th edition 2E.1 mistake ?

Postby CateJensen3K » Wed Nov 28, 2018 9:44 pm

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.

Jasmin Argueta 1K
Posts: 69
Joined: Fri Sep 28, 2018 12:16 am

Re: 7th edition 2E.1 mistake ?

Postby Jasmin Argueta 1K » Thu Nov 29, 2018 12:38 am

I'm also very confused. I thought adding any lone pairs would change the shape completely.

Dakota_Campbell_1C
Posts: 51
Joined: Fri Sep 28, 2018 12:15 am

Re: 7th edition 2E.1 mistake ?

Postby Dakota_Campbell_1C » Thu Nov 29, 2018 12:52 am

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.

Nikki Bych 1I
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

Re: 7th edition 2E.1 mistake ?

Postby Nikki Bych 1I » Thu Nov 29, 2018 11:08 am

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.

Sona Hakobyan 3J
Posts: 45
Joined: Fri Sep 28, 2018 12:25 am

Re: 7th edition 2E.1 mistake ?

Postby Sona Hakobyan 3J » Thu Nov 29, 2018 2:18 pm

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.

Henri_de_Guzman_3L
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

Re: 7th edition 2E.1 mistake ?

Postby Henri_de_Guzman_3L » Thu Nov 29, 2018 7:11 pm

Got it! AX2E3 is linear with three equatorial lone pairs.


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