Hybridization: Localized Electron Model

Hybridization Overview

http://www.chemistryland.com/CHM151S/09-CovalentBonds/Covalent.html

Why Hybridization Occurs Example: Methane (CH4) 4 hydrogens bonded to the central carbon

atom The 4 electrons involved in bonding on the C

atom are: 2s2

2p2

Which of these electrons have higher energy levels?

But all 4 bonds have the SAME energy level.

Why Hybridization Occurs (continued)

To accomplish this “same energy level bonds” arrangement, the 4 electron orbitals “hybridize” to a combined s and p orbital, with energy somewhere between the two original s and p orbitals.

Carbon Hybridization

Hybridization Generalizations

Hybridizations refer to effective pairs! A double bond is how many effective

pairs? A triple bond is how many effective pairs?

4 effective pairs = sp3 orbitals 3 effective pairs = sp2 orbitals 2 effective pairs = ????? 5 effective pairs = ?????

sp2 Hybridization

Example: H2CO Central atom? How many effective pairs around the central

atom? What electrons on the C atom are involved in

bonding (are valence electrons)? This time, the 2s2 and 2p2 electrons only need

to hybridize to form 3 orbitals. You will have 3 sp2 hybrid orbitals and a lone

original p orbital.

H2CO Carbon Hybridized Orbitals

H2CO Oxygen Orbitals How many effective pairs exist around the

oxygen atom in H2CO? What type of hybridization is this? In the molecule, how may of each of the

following exist? Lone pairs Single bonds Double bonds Hybrid orbitals on the C atom Hybrid orbitals on the O atom Regular (unhybridized) orbitals on C/O atoms

sp2 Hybridization and Double Bonds

σ (“sigma”) bonds join the atoms together in single OR multiple bonds.

In a multiple bond, π bonds are composed of overlapping regular p orbitals parallel to the main σ bond.

H2CO Orbital Diagram

What is missing from this orbital diagram???

sp Hybridization How many effective pairs would be on

an atom with sp hybridization? If we are still examining C, which

electrons (and orbitals) are involved in bonding?

So what would the new orbitals be AFTER hybridization?

Example: acetylene (ethyne) C2H2

dsp3 Hybridization

How many effective pairs on the atom? Why can’t we use C as an example? Give me an element we CAN use. Example 1: (using element provided) Example 2: I3

-1

Determine the BEST Lewis structure based on formal charges.

Examine the bond types on each I atom.

6 Effective Pairs

What would the hybridization be? Give an example of a molecule you

have “seen” that has 6 effective pairs.