1. A Review of General Chemistry

Draw the resonance contributors of the cyclooctatrienyl dianion.

b. Which of the resonance contributors makes the smallest contribution to the hybrid?

Are the following pairs of structures resonance contributors or different compounds?

d.

e.

a. Draw resonance contributors for the following species. Do not include structures that are so unstable that their contributions to the resonance hybrid would be negligible. Indicate which are major contributors and which are minor contributors to the resonance hybrid.

b. Do any of the species have resonance contributors that all contribute equally to the resonance hybrid?

14.

Which of the following is the most stable resonance structure for the $CNO-$ ion when nitrogen is the central atom?

Draw the important resonance forms of the following free 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)

Which of the following is a valid resonance structure for the acetate ion ${\mathrm{CH}}_3{\mathrm{COO}}_{-}$?

Which of the following statements best describes the relationship between resonance structures of a $\mathrm{carbocation}$?

a. Draw resonance contributors for the following species. Do not include structures that are so unstable that their contributions to the resonance hybrid would be negligible. Indicate which are major contributors and which are minor contributors to the resonance hybrid.

b. Do any of the species have resonance contributors that all contribute equally to the resonance hybrid?

9.

Benzyl bromide is a primary halide. It undergoes S_N1 substitution about as fast as most tertiary halides. Use resonance structures to explain this enhanced reactivity.

Draw the Lewis structure of azidomethane (CH₃N₃) [Show two important resonance structures.]

a. Draw resonance contributors for the following species, showing all the lone pairs:

b. For each species, indicate the most stable resonance contributor.

3. NO₂^-

Draw the important resonance forms for the following molecules and ions.

(d) NO₃^–

(e) NO₂^–

(f)

Draw the resonance contributors for the following radicals:

d.