1. A Review of General Chemistry

Use resonance structures to identify the areas of high and low electron density in the following compounds:

(d)

Identify the resonance structure that will be produced given the molecule shown and the electron flow indicated.

(a)

Which statement best describes the use of curved arrow notation when drawing resonance structures in organic molecules?

Acetonitrile (CH₃C≡N) is deprotonated by very strong bases. Write resonance forms to show the stabilization of the carbanion that results.

For each pair of ions, determine which ion is more stable. Use resonance forms to explain your answers.

(e)

(f)

For each of the following compounds, draw the important resonance forms. Indicate which structures are major and minor contributors or whether they have the same energy.

(c) [H₂COCH₃]⁺

Two resonance structures are shown for each molecule. Use the arrow-pushing formalism to represent the electron flow from the structure on the left to the one on the right.

(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?

5.

Draw another resonance form for each of the substituted allylic cations shown in the preceding figure, showing how the positive charge is shared by another carbon atom. In each case, state whether your second resonance form is a more important or less important resonance contributor than the first structure. (Which structure places the positive charge on the more-substituted carbon atom?)

Use resonance structures to identify the areas of high and low electron density in the following compounds:

g.

h.

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.

Each pair of structures represents two valid resonance structures. Use the arrow-pushing formalism to justify the formation of the one on the left from the one on the right.

(a)

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?

8.