1. By: Tina, India, Shelby, Zain
Resonance Structures
By: Tina, India, Shelby, Zain

2. Resonance Structures
Resonance structures are alternative forms of Lewis structures that give and equally accurate description of a single molecule.
Used when there are multiple ways to show bonds in a Lewis structure diagram of a molecule

3. Resonance Structures NO3-
One nitrogen-oxygen double bond, two nitrogen-oxygen single bonds
Double headed arrows indicate contributing resonance structures
Structures have the same types of bonds and electron positions, but are not identical; position of nitrogen-oxygen double bond makes them different
Measurements show all bond lengths are equal because the three bonds are intermediate between single and double

4. Resonance Structures NO2+
It is important to count electrons to determine the bonds when drawing Lewis structures, in case there are no resonance structures
The structure for NO2+ can be misleading, because of the positive charge, which indicates an electron needs to be added
This makes two nitrogen-oxygen double bonds, so no resonance structures

5. Examples CO3-2 First draw the Lewis structure
Count the electrons: O3 has 18, C has 4
Add the two electrons to get a total of 24, this means there should be 12 electron pairs
Because there is one carbon-oxygen double bond and two carbon-oxygen single bond, two more structures need to be drawn with the double bond on a different oxygen

6. Examples SO2 First draw the Lewis structure
Count the electrons: O2 has 12, S has 6
The total number of electrons is 18, this means there should be 9 electron pairs
Because there is one sulfur-oxygen double bond and one sulfur-oxygen single bond, another structure needs to be drawn with the double bond on a different oxygen
A third structure needs to be drawn where there are two double bonds because another double bond can fit the Lewis structure