Hybrid orbitals when given a long formula

[Mariah Tumbaga 1e]

When given a formula like CH3CHCHCN and the two lasts Cs are underlined and asked what hybrid orbitals are being used, how do you figure this out?

[WhitneyLaValle4A]

First of all, the long form is giving you a clue as to how to draw the lewis structure. So once you draw it out according to the long form of the formula given. Then, once it is all drawn- count the number of regions of electron density surrounding the underlined atom. Each atom bonded to it, or lone pair, counts as one region of electron density. The amount of regions of electron density should add up to the exponents of the hybridization- for example, 2 regions is sp, 3 regions is sp^2, 4 regions is sp^3, and then you expand into the d orbitals

[Divya Prajapati 1E]

When you are given a "long formula" you first need to write out the Lewis structure. The reason the formula is so long is to guide you in creating this structure. As you read the formula left to right, place atoms in order of how they are given to you, usually with carbon atoms attached to each other in a long chain.

Once you come up with a Lewis structure, make sure the valence electron count is correct. If not, add double bonds or lone pairs. In this case, the 2nd and 3rd carbon atoms are double bonded to each other, the 4th carbon is triple bonded to nitrogen, and the nitrogen has one lone pair.

Now that you have found this Lewis structure, just look at the underlined carbon atoms and find out their hybridization as you would in any other compound. The 3rd carbon has a double bond and two single bonds, meaning it is sp2 hybridized. The 4th carbon has a single bond and a triple bond, meaning it is sp hybridized.

[Mariah Tumbaga 1e]

oh okay! Thank you! That helps, I was thinking it was asking for something else.