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4.21 a

Posted: Thu Jun 07, 2018 9:51 pm
by Husnia Safi - 1K
Why is the answer trigonal planar with 120 degree angles when there are 5 regions of electron density?

Re: 4.21 a

Posted: Thu Jun 07, 2018 9:57 pm
by ElizabethP1L
Hi! There are not five regions of electron density. The way the Lewis structure looks like is a double bond between 2 carbon atoms and two H atoms attached to each carbon. Since there are two central atoms here, we count the regions of electron density separately. You'll notice that around a single atom of carbon there are 3 regions of electron density (the double bond with C and two single bonds with H). This is a trigonal planar shape with a 120 degree angle! This same shape/bond angle is observed for the other C atom in the structure. There are not 5 regions of electron density since we have 2 central atoms! Hope this helped! :)