AP Chemistry - Chapter 9

Hybridization

the combining of two or more orbitals nearly equal energy within the same atom forming orbitals of equal energy

sp³ hyrbrid orbitals

an s orbital is combined with three p orbitals to create four equal hybrid orbitals

has an electron-pair geometry of tetrahedral

How do you think the energies of these new hybrid sp³ orbitals compare to the original s and p orbital energies they are made from?

The energy of the sp³ orbital is the average energy of the s orbital and p orbitals.

The sp³ orbital have MORE energy than the 2s orbital and LESS energy than the 2p orbital.

sp² hyrbrid orbitals

combines two orbitals from a p sublevel with one orbital from an s sublevel to make three identical hybrid orbitals

What happens to the remaining unhybridized p orbital?

The remaining p orbital (pair of electrons) keeps its “normal shape“ and remains perpendicular to the sp² orbital.

sp hyrbrid orbitals

one s orbital combines with a single p orbital to create two sp hybridized orbital — leaving two normal p orbitals

sigma bonds

exist in the region directly between two bonded atoms

pi bonds

exist in the region above and below a sigma bond between two atoms

How many sigma and pi bonds are in a…

single bond

double bond

triple bond

1 sigma bond

1 sigma bond, 1 pi bond

1 sigma bond, 2 pi bond

The De-Localized Electron Model

The sharing of unhybridzed p-orbitals that allows for resonance.

isomers

same molecular formula, different chemical structure

Are these isomers?

Note: Single bonds allow rotation about a bond. Double and triple bonds do not allow rotation.

No, they have different molecular formulas.

Are these isomers?

Note: Single bonds allow rotation about a bond. Double and triple bonds do not allow rotation.

Yes, they have the same molecular formula, but different chemical structures.

Are these isomers?

Note: Single bonds allow rotation about a bond. Double and triple bonds do not allow rotation.

No, they have the same structure if you rotate it.

Are there pi bonds present in each of these models?

Can the central bond rotate?

Are any molecules identical?

Which, if any, are isomers?

Yes, they can be located in the double bonds.

No, this is due to the double bonds between the two Carbon atoms.

No, even if you can rotate them they won’t look identical to each other.

#2 and #3 are isomers