2.2G Hybridization

Tell me about the Theoretical and Experimental Structures of Methane. Why is the problem between the structure of carbon and methane?

Experimental evidence shows that carbon is tetrahedral

All four C–H bonds are the same

To get methane, carbon would need to have four identical orbitals

Each orbital would hold 1 electron and form one σ-bond

However...

What is Hybridization? What does it involve? Where does it occur?

the mixing atomic orbitals to form new hybrid orbitals for bonding.

• involves promoting electrons and merging orbitals in order to get new orbitals, whose shapes match experimental evidence.

• Hybridization can occur in any covalently bonded molecule.

Tell me about sp³ orbitals

• Hybridization gives a model that matches bond geometry

• sp³ orbitals have 25% s-character and 75% p-character

• 109.5° apart from one another

Tell me about Ethene and how it relates to hybridization.

π-bonds form via side-to-side overlap of p-orbitals

If a double bond is present, a p-orbital must still remain after hybridization

Tell me about sp² orbitals

sp² look like sp³ but are shorter and wider

sp³ orbitals are oriented 120° apart from one another

sp orbitals

Shortcut for Determining Hybridization

Steps

1. Look at atom in molecule

2. Count the number of electron domains

2 E.D. = sp

3 E.D. = sp²

4 E.D. = sp³

5 E.D. = sp³d

6 E.D. = sp³d²

What do the superscripts (exponents) tell you?

how many of each orbital was used in hybridization