Which statement about resonance structures is TRUE:

1) There can never be more than two resonance structures for any molecule.
2) Only ionic compounds use resonance structures
3) The real structure of a molecule is an average or hybrid of the resonance structures
4) Resonance structures are used when chemists are unsure of the true structure.

I believe it is 3....?

Yes, you are correct. Statement 3) "The real structure of a molecule is an average or hybrid of the resonance structures" is true.

Resonance structures are different Lewis structures that can be drawn for a molecule or ion when there are multiple ways to arrange the electrons. These structures are connected by double-headed arrows.

The real structure of the molecule is not described by any single resonance structure but is rather a hybrid, or combination, of all the resonance structures. The actual arrangement of the electrons is represented by the average of the resonance structures.

This phenomenon is known as resonance and is common in molecules with conjugated systems, such as benzene.

Yes, you are correct. Statement 3, "The real structure of a molecule is an average or hybrid of the resonance structures" is true.

To understand why this statement is true, let's first define resonance structures. Resonance structures are different Lewis structures that can be drawn for a molecule when it has delocalized electrons, such as in compounds with multiple bonds or lone pairs of electrons. Resonance structures are represented by double-headed arrows, indicating the movement of electrons.

Now, onto the explanation for why statement 3 is true. Resonance structures are not separate, discrete entities. Instead, they are just different ways of representing the same molecule, where the location of electrons is shown differently. In reality, the actual electron distribution within the molecule is a blend or hybrid of the resonance structures.

This concept is known as resonance hybridization. The resonance hybrid incorporates the characteristics of each resonance structure, and the final structure represents the average of all possible resonance structures. The resonance hybrid is more stable and energetically favorable compared to any individual resonance structure.

It is important to note that the concept of resonance is not limited to ionic compounds or compounds with specific characteristics. Resonance can be observed in a variety of molecules and compounds, including both organic and inorganic compounds.

To summarize, statement 3 is true: the real structure of a molecule is an average or hybrid of the resonance structures.

Go to the head of the class.