Resonance, bond strength and
Length
Please turn off all downloads. You can usually pause them by clicking on them and clicking pause. Facebook
and youtube are officially banned during class time
(this is not me micromanaging, it’s a legit internet issue as told to me by OIT).
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Remember back 5
rows of even side
are no seating zones
• Any common octet breaking atoms?
[HCO2]-
• How many electrons are present?
• What is the central atom?
+0
• Draw a skeletal structure
• Add electrons: do you have enough
to give all atoms octets?
• Yes? Then minimize formal charges if
needed.
• No? Then add double bonds until
you have enough electrons.
• Is it one that is typically found
to have less?
• Is there any reason you chose
those double bonds rather
than placing it elsewhere?
H
+0
O
O
C
C
+0
-1
O
H
+0
• No? Then draw
resonance structures to
show all equally likely
structures
• Label each with the formal charge
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-1
+0
O
+0
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+0
H
+0
O
O
C
C
+0
-1
O
-1
What is the charge on each oxygen?
Hint: they are the same!
+0
H
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+0
+0
O
Word of the day: learning
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What is the bond order of the CO bond?
Hint: they are the same!
O3
6(3)=18 electrons.
• Any common octet breaking atoms?
• How many electrons are present?
O
• What is the central atom?
• Draw a skeletal structure
O
• Add electrons: do you have enough to give all atoms
octets?
Short 2 electrons
Need one bond
O
• Yes? Then minimize formal charges if needed.
• No? Then add double bonds until you have enough
electrons.
+1
O
• Is it one that is typically found to have less?
• Is there any reason you chose those double
bonds rather than placing it elsewhere?
• No? Then draw resonance structures to
show all equally likely structures
• Label each with the formal charge
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Word of the day: learning
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LearningCatalytics: session ID: 35789297
+1
O
+0
O
O
O
-1
-1
O
+0
+1
+1
O
O
+0
What is the charge on the outside oxygens?
Hint: they are the same!
O
O
-1
O
-1
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O
+0
What is the bond order of the bonds?
Hint: they are the same!
Word of the day: learning
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you select “allow”.
[SO3]2-
O
6*4+2=26 electrons
+1 S
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-1
-1
O
O
-1
+0
+0
-1
O
S
-1
O
O
+0
-1
O
+0 O
S
All have octet,
Can we minimize
formal charge?
-1
O
O
+0
-1
-1
S
O
Bond order: 4 bonds divided by 3 structures
Charge: -2 total charges divided by 3 atoms
4/3
-2/3
O
+0
Line Structures: CH3CHCHCOOH
• Rules
• The end of a line, or a corner is a carbon
H3C---CH2---CH2----CH3
• All hydrogens attached to a carbon are assumed
to be there. Do not draw them.
• Don’t forget the three hydrogens attached to the
carbon at an end of a line are there!
• Heteroatoms: aka atoms other than C and H,
need to be written in.
• All hydrogens attached to heteroatoms must be
drawn in.
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H3C---CH---CH----CH3
O
OH
H3C---CH---CH----COOH
Line Structures: NH2CH2CH(OH)CH3
• Rules
• The end of a line, or a corner is a carbon
• All hydrogens attached to a carbon are assumed
to be there. Do not draw them.
H2N
H2N---CH2---CH2----CH3
• Don’t forget the three hydrogens attached to the
carbon at an end of a line are there!
• Heteroatoms: aka atoms other than C and H,
need to be written in.
• All hydrogens attached to heteroatoms must be
drawn in.
H2N
OH
H2N---CH2---CH(OH)----CH3
• BENZENE
• C6H6
C6H12
• 6-membered ring
• Draw the lewis structure
• Be sure to include any resonance structures
Add double bonds to decrease,
Hydrogens present.
• Draw the line structure
• Be sure to include any resonance structures
C6H6