1. A Review of General Chemistry

Draw the resonance contributors for the phenolate ion.

Draw resonance contributors for the following ions:

d.

a. Predict the relative bond lengths of the three carbon–oxygen bonds in the carbonate ion.

b. What is the charge on each oxygen?

Draw resonance contributors for each of the following species and rank them in order of decreasing contribution to the resonance hybrid. Then draw the resonance hybrid.

e.

Draw resonance contributors for each of the following species and rank them in order of decreasing contribution to the resonance hybrid. Then draw the resonance hybrid.

b.

Draw resonance contributors for each of the following species and rank them in order of decreasing contribution to the resonance hybrid. Then draw the resonance hybrid.

c.

Draw resonance contributors for each of the following species and rank them in order of decreasing contribution to the resonance hybrid. Then draw the resonance hybrid.

d.

Draw resonance contributors for each of the following species and rank them in order of decreasing contribution to the resonance hybrid. Then draw the resonance hybrid.

f.

Which of the following has delocalized electrons?

a.

b.

c.

Draw all resonance structures of the following carbanion and carbocation.

(a)

(b)

How many atoms share the unpaired electron in semiquinone?

Draw the resonance contributors for the following radicals:

a.

Another way the preceding might be presented is to say that the minor resonance structure(s) reveal the reactivity of a molecule. Show how the minor resonance structure(s) can help us understand that the following reactions occur with the regioselectivity shown.

(a)

(b)

(c)

A carboxylic acid has two oxygen atoms, each with two nonbonding pairs of electrons.

(a) Draw the resonance forms of a carboxylic acid that is protonated on the hydroxy oxygen atom.

(b) Compare the resonance forms with those given previously for an acid protonated on the carbonyl oxygen atom.

(c) Explain why the carbonyl oxygen atom of a carboxylic acid is more basic than the hydroxy oxygen.

Draw the resonance contributors of the peptide bond in the less stable configuration.