Resonance Structures Ac
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Transcript of Resonance Structures Ac
• I can draw a Lewis structure, including resonance structures when necessary, for a given molecule
Learning Targets
• So far, we’ve learned how to draw a Lewis structure to represent the covalent bonding that occurs in a molecule.
• Sometimes there is more than one possible Lewis structure for a molecule.
• All of the possible Lewis structures for a molecule are called “resonance” structures.
Resonance Structures
• Resonance structures are drawn using the same rules for Lewis structures.
• Resonance is possible when multiple bonds are necessary to create an octet on the central atom.
• If there is a choice when choosing a pair of electrons to move into a multiple bond, then there are resonance structures.
• Resonance structures are possible ONLY if there is a choice when creating multiple bonds.
Resonance Structures
• A double headed arrow ( ) is used in between the structures to indicate that they are in resonance with one another.
• Ozone, O3
Practice ProblemsDraw all possible resonance structures for the following molecules.
• Ozone, O3
Practice ProblemsDraw all possible resonance structures for the following molecules.
O OO. . . .
. .. .
. .
. .. .
• Ozone, O3
Practice ProblemsDraw all possible resonance structures for the following molecules.
O OO. . . .
. .. .
. .
. .. .
Central atom octet not satisfied!
• Ozone, O3
Practice ProblemsDraw all possible resonance structures for the following molecules.
O OO. . . .
. .. .
. .
. .. .
One pair needs to be shared.
?
• Ozone, O3
Practice ProblemsDraw all possible resonance structures for the following molecules.
O OO. . . .
. .. .
. .
. .. .
If you have a choice, resonance structures exist!
?
• Ozone, O3
Practice ProblemsDraw all possible resonance structures for the following molecules.
Ozone has two resonance structures. The completed structures have all octets satisfied.
O OO. . . .
. .. .. .
. .
OO O. .. .
. . . .. .
. .
• Carbon Dioxide
Practice ProblemsDraw all possible resonance structures for the following molecules.
• Carbon Dioxide
Practice ProblemsDraw all possible resonance structures for the following molecules.
C OO. . . .
. .. .
. .. .
Central atom octet not satisfied!
• Carbon Dioxide
Practice ProblemsDraw all possible resonance structures for the following molecules.
C OO. . . .
. .. .
. .. .
Two pairs need to be shared with carbon.
?
• Carbon Dioxide
Practice ProblemsDraw all possible resonance structures for the following molecules.
C OO. . . .
. .. .
. .. .
You have a choice. Therefore, resonance structures exist.
?
• Carbon Dioxide
Practice ProblemsDraw all possible resonance structures for the following molecules.
C OO. .
. .
. .. . CO O. .
. .
. . . .CO O. .
. .
. .
. .
Carbon dioxide has three resonance structures. The completed structures have all octets satisfied.