These Are Not the Bonds You're Looking For: Introduction to Resonance Structures

A parody of one scene in Star Wars Episode IV A New Hope. Obi-Wan Kanobi, Luke Skywalker, C3PO and R2D2 enter Mos Eisley on Tatoonie.  They are stopped by Stormtroopers and questioned about the droids they are transporting.  In the skit, Obi-Wan Kanobi and Luke Skywalker are transporting ozone and calcium carbonate.  Stormtrooper #1:  "How long have you had these molecules?"   Luke Skywalker: "One or two seasons"   Stormtrooper #2 "These molecules look like they have single and or double bonds".  Obi-Wan Kanobi [with a small wave of his hand}: "You should measure the bond lengths and bond energies in the ozone molecule".  Stormtroopers #1 and #2 [together]: "We should measure the bond lengths and bond energies in the ozone molecule".  see script  etc  etc  Obi-Wan Kanobi [with a small wave of his hand}: "These are not the bonds you're looking for".     Stormtroopers #1 and #2 [together]:  "These are not the bonds we're looking for". 

David R. (Randy) Sullivan and Thomas J. Greenbowe, Department of Chemistry & Biochemistry, University of Oregon, Eugene, OR 97403 USA

Storm Trooper #1:  Have long have you had these molecules?

Luke Skywalker: Two or three seasons.

Storm Trooper #2: Looks like you are transporting molecules with chemical bonds.

Storm Trooper #1: We are looking for molecules with Single bonds and or Double bonds.  These types of molecules will be detained for questioning.

Storm Trooper #2: These molecules sure look like they have single or double bonds.

Ben Obi-Wan Kenobi: [with a small wave of his hand]

You should measure the bond lengths and the bond energies in ozone.

Storm Troopers #1 and #2 [together]: We should measure the bond lengths and bond energies in Ozone.

Storm Trooper #1: [uses a yard stick and measures the bond lengths of the oxygen-oxygen bonds in ozone.] 

Storm Trooper #1 [looks at Trooper #2]: These oxygen-oxygen bonds all have the same bond length.   pause   Single bonds are longer than double bonds.  These can’t be single or double bonds. You better measure the bond energies.

Storm Trooper #2 [uses a phone with the i-phone, sound app with waves space music, to measure the bond energies]: [looks at Trooper #1] These oxygen-oxygen bonds all have the same bond energy. [pause]  Double bonds have a larger bond energy compared to single bonds. These can’t be single or double bonds.

Ben Obi-Wan Kenobi: [with a small wave of his hand]  The Ozone molecule turns over its Lewis Structure Placard

Yes  You are correct.  Look again.  You see the oxygen bonds in ozone all have the same bond length and bond energy!
Ben Obi-Wan Kenobi: [with a small wave of his hand]  These bonds do not have a bond order of one or a bond order of 2.  Do you see the bond order?

Storm Trooper #1 and #2: [shake their heads]   No.

Luke Skywalker: All of the bonds in this ozone molecule have the same bond length and bond strength they can't be single bonds or double bonds.

Ben Obi-Wan Kenobi:  If you take the double bond and single bond and add them together    2 + 1 = ?

StormTroopers (together]:  3

Ben Obi-Wan Kenobi:  Since there are two bonds.  Take the 3 and divide by 2 regions of electron density.  3 divided by 2 is  ?

StormTroopers (together]:  one and a half

Luke Skywalker: Now you see it.  The bond order in each bond is 1.5

Storm Trooper #1:  That’s weird.  How can that be?

Ben Obi-Wan Kenobi: These bonds are resonance stabilized.  The electrons are delocalized. The ozone molecule is especially stable and this molecule is of no concern to you.

Curriculum Notes 

This skit is performed just as resonance structures are being introduced.

© Copyright 2012 Email: Randy Sullivan, University of Oregon Chemistry Department and UO Libraries Interactive Media Group