Chem100/11 2013

Assignment 7 (chapters 8 and 9)

I. Drawing Lewis Structures (8.5-8.8).

For each structure, report total number of valence electrons. Show nonbonding (lone) electron pairs and formal charges.

1. {10} Draw the Lewis structure for the following molecules and ions.

C₂H₂ (acetylene), C₂H₄ (ethane), ClO₄^-, CO, NH₄⁺

2. {10} Draw resonance Lewis structures for the following molecules and ions. :

O₃ (ozone), C₆H₆ (benzene), CH₃CO₂^- (acetate), NO₂^-, NO₃^-, OCS.

3. {10} Draw the Lewis structures for the systems below and explain briefly violations of the octet rule.

AlH₃, XeF₄, ICl₂^-, SbF₅, BeCl₂

4. {10} Use Table 8.4 to estimate the enthalpy change for the following reaction:

H₂ + C₂H₄ à C₂H₆

II. Molecular Shapes, the VSEPR model, Hybridization theory

5. [40] Use the Lewis structures and VSEPR theory to predict the electron domain geometry, ED geometry, and molecular geometry, M geometry, of the systems below. Draw the structures. For each structure indicate dipole moment, μ, (zero or not) and hybridization on central atom.

ED geometry M geometry μ hybridization on central atom

a) OF₂ Tetrahedral bent nonzero sp³

b) AlCl₄^-

c) I₃^-

d) ICl₅

e) BH₃

f) H₃O⁺

g) PHCl₂

h) XeF₄

i) NH₄⁺

j) PH₃

6. {10} Problem 9.64 from the text.

7. {10} Problem 9.66 from the text