High School Chemistry : Help with Resonance
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Example Question #1 : Help With Resonance
When will resonance be possible in a molecule?
The molecule must contain carbon atoms
The molecule must only contain single bonds
The molecule must contain a double or triple bond adjacent to a single bond
The molecule must contain oxygen or nitrogen
The molecule must have a triple bond adjacent to a single bond
The molecule must contain a double or triple bond adjacent to a single bond
Resonance is the movement of electrons from one bond to another. This helps to shift the electron distribution between multiple atoms, creating molecular stability. In order for resonance to occur, there must be a pi bond next to a sigma bond. A pi bond is a double bond or triple bond and a sigma bond is a single bond. During resonance, the electrons from the pi bond move around causing the double (or triple) bond to shift positions. This frequently occurs with oxygen and nitrogen because they have several valence electrons and can readily form pi bonds, but these elements are not required to form resonance structures.
Example Question #2 : Help With Resonance
Which of the following best explains the concept of resonance structures?
Certain molecules exist in nature whose structures may have two or more different forms based on the instantaneous locations of electrons within the molecule
Chemists are unsure of the structures of some molecules, so they use resonance structures to model several possibilities at once
Certain elements exist in nature in several different isotopes
Certain molecules exist in nature whose structures may have two or more different forms based on the locations of atoms within the molecule
Certain molecules exist in nature whose structures may have two or more different forms based on the instantaneous locations of electrons within the molecule
Resonance structures are a way of describing the different possible locations of delocalized electrons within a molecule. Although a molecule might have several correct resonance forms, often, one is more stable than the others. Molecules whose structures differ in the locations of atoms are called isomers.
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