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Hybridization
[Animated Website (mhhe) for Hybridized Orbitals]
1st year Rules for Determining Hybridization (Always on Central Atom only)
1.Count the number of outside atoms that central atom is bonding with.
2.Count the number of lone pairs on central atom
3.Add together to get number.
4.This number is number of Hybridized orbital
Example CH4
Central atom is bonded to 4 outside atoms and no lone pair so hybridization is sp3 where there are 4 of them.
Correct Explanation: Will use Some Organic Chemistry to explain
OVERALL RULE : # OF ATOMIC ORBITALS IN = # OF HYBRIDIZED ORBITALS OUT
We will explain hybridization in more detail via the major families of Hydrocarbons (cpds with just C and H combining)
Alkanes [NYU website showing the first several alkanes 3-D structure and general info]
Bonding / hybridization:
General Chemical Formula:
Shape of Molecule
[Dr. Blaber site with 3-D hybridized orbital]
Name compounds by finding longest carbon chain (C bonded to C bonded to C, etc) via the prefixes found in [Prefixes for Hydrocarbons] and adding the ending -ane.
Example: CH3CH2CH3, 3 C on the backbone, prefix name is prop- so since it is an Alkane you add -ane to end of prefix to get propane.
Alkenes
Bonding / hybridization:
General Chemical Formula:
Shape of Molecule
[Website to get to Erik's Ethene Animation]
[Dr. Blaber site with 3-D hybridized orbital]
sigma bond
double bond
Multiple Bonds need atomic p orbitals for Pi bonds
Naming alkenes are more complecated than alkanes since your double bond can be between various carbons. You indicate with a number in front of the name to show which carbon the double bond is on. You always count backbone carbons (and use prefix as in alkane) so that this number is miminal. The ending for alkenes is -ene
Example: CH3=CH-CH2CH3
There are 4 carbons in backbone (but-) and it is an alkene (at ending -ene), the double bond is on the first carbon so it is called 1-Butene.
Note: In the old days, they did not use this naming system. They would call the above chemical, butylene (you see this in a plastic called polyethylene, it is derived form ethene or ethylene).
Alkynes
Bonding / hybridization:
General Chemical Formula:
Shape of Molecule
[Dr. Blaber site with 3-D hybridized orbital]
Similarly, alkyne naming can be completed. It does the same numbering system as alkenes to show location of triple bond. The ending here is -yne.
Example: CH=CH (can not show triple bond since need three parallel lines, computer can't do it
There are 2 C in backbone (eth-) and add -yne to get ethyne. Since there can only be one place for triple bond, there is no number needed. There is an old naming system here also. The above compound is called acteylene (used in arc welding with oxygen gas).
Molecules with More than One Multiple Bond attached to Central Atom
Bonding / hybridization:
Shape of Molecule
Hybridization of Central Atoms that Exceed the Octet Rule
Since you need more than 4 atomic orbitals ( 1 s and 3 p)to make your 5 or 6 hybridized orbitals, where do you get the extra atomic orbitals?
Does this help you to explain why some elements can't be the central atom when you exceed the Octet Rule?
MOLECULAR ORBITAL THEORY (most of Ch 9 in Zumdahl) WILL NOT BE DISCUSSED