CHM 501

Homework 1

Due February 10, 2016



1. Give the electron configuration for the following atoms or ions: Fe, Fe2+, Cu, Cu+.

Fe [Ar]4s23d6

Fe2+ [Ar]3d6

Cu [Ar]4s13d10

Cu+ [Ar]3d10

2. Draw the lowest energy Lewis dot structures for each of the following and give the formal charge and the oxidation number for each atom in the molecule: a) SO3; b) XeO3; c) BrF3; d) IF5.

a) SO3 formal charges: S = 0, O = 0; oxidation numbers: S = +6, O = –2

b) XeO3 formal charges: Xe = 0, O = 0; oxidation numbers: Xe = +6, O = –2

c) BrF3 formal charges: Br = 0, F = 0; oxidation numbers: Br = +3, F = –1

d) IF5 formal charges: I = 0, F = 0; oxidation numbers: I = +5, F = –1

3. Draw the structures of each of the molecules in question 2 and estimate all of the bond angles in each.

a) SO3 trigonal planar, all O-S-O angles = 120°

b) XeO3 pyramidal, all O-Xe-O angles ~ 108° (slightly less than the perfect tetrahedral angle)

c) BrF3 bent T-shaped, two F-Br-F angles ~ 89° and one F-Br-F angles ~ 179°

d) IF5 square-based pyramid, two F-Br-F angles ~ 89° and one F-Br-F angles ~ 179°

4. Give the point group for each molecule in question 2.

a) SO3 D3h

b) XeO3 C3v

c) BrF3 C2v

d) IF5 C4v