Name:

Atomic and Molecular Orbitals Deadline: April 12, 2014

Homework #3

1. Write Lewis structures that obey the octet rule for each of the following molecules and

ions. (In each case the first atom listed is the central atom.) Assign the formal charges for

each central atom.

a. POCl3, SO42-

, XeO4, PO43-

, ClO4-

b. NF3, SO32-

, PO33-

, ClO3-

c. ClO2-, SCl2, PCl2

-

2. Write Lewis structures for the species in Exercise 1 that involve minimum formal

charges.

3. Write Lewis structures for the following molecules:

a. formic acid, HCOOH;

b. acetonitrile, CH3CN;

c. vinyl chloride, CH2CHCl

Name:

Atomic and Molecular Orbitals Deadline: April 12, 2014

4. Write Lewis structures for the following. Show all resonance structures where applicable.

a. NO2-, NO3

-, N2O4 (N2O4 exists as O2N-NO2.)

b. OCN-, SCN-, N3- (carbon is the central atom in OCN

- and SCN

-)

5. Nitrous oxide (N2O) has three possible Lewis structures:

(i) Given the following bond lengths, rationalize the observations that N N bond

length in N2O is 112 pm and that the N O bond length is 119 pm.

(ii) Assign formal charges to the resonance structures for N2O. Can you eliminate any

of the resonance structures on the basis of formal charges? Is this consistent with

observation?