## Question 4.95

$sp, sp^{2}, sp^{3}, dsp^{3}, d^{2}sp^{3}$

Dayna Pham 1I
Posts: 98
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 3 times

### Question 4.95

Attached is the solution to question 4.95, which asks:

Consider the bonding in CH2-CHCHO. (a) Draw the most important Lewis structure. Include all nonzero formal charges. (b) Identify the composition of the bonds and the hybridization of each lone pair—for example, by writing sigma(H1s,C2sp2).

My questions regarding the figure attached are:

1) Why are the pi bonds only C 2p to O 2p instead of (C 2sp2, O 2sp2)?

2) In addition, I thought terminal atoms are usually not hybridized, like hydrogen. Why is oxygen hybridized in this case? Is it because oxygen is 2p4 and has only two unpaired electrons, but wants to make more bonds than two?

Thanks!
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Camille Marangi 2E
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

### Re: Question 4.95

The pi bonds can't be attached to hybrid orbitals due to their rigidity, just as Lavelle explained in his lecture last Monday. Also I think it's not that terminal atoms are most often not hybridized, rather that hydrogen isn't hybridized and it is often the terminal atom. Oxygen in this molecule has 3 areas of electron density and using Lavelle's shortcut (Regions of electron density= Number of hybrid orbitals) we get a hybridization of sp2.