Problem Set #1
September 3, 2012
Due Monday September 10, 2012
Chem 417
Fall 2012
Unit 1 on Structure & Bonding.
INSTRUCTIONS. Please solve these problems on your own paper in this order. A single copy of the answers
is to come from each group, in which all the members are expected to contribute substantially equally to
solving the problems. Turn in with all names on your Problem Set group on the first page.
*** Groups this time are the pairs that worked together on the first “Dr. Mattson” pages ***
1.
2.
3.
4.
5.
6.
7.
Problem 2.18 (References to “Problems” refer to the end-of-chapter problems in the M&T text)
Problem 2.26
Problem 2.28
Problem 2.40
Problems 2.27 & 2.34 (are they related?)
Problem 2.30
Give Lewis dot structures and sketch shapes for: SOCl2, N3– and NO2. Classify
each molecule as polar or non-polar.
8. Draw resonance structures for the isoelectronic compounds NSO– and SNO–.
Assign formal charges. For each ion, choose the best resonance structure. Of the
two ions, which do you predict to be the more stable, and very briefly why?
9. Formation of anions from neutral atoms results in an increase in size, but
formation of cations from neutral atoms results in a decrease in size. What causes
these changes?
10. The oxide ion and the fluoride ion both have the same electronic structure, but the
oxide ion is larger. Why?
11. Please write the ground state electron configuration for the following atoms and
ions: Se, Se2–, V, V4+. The use of the inert core formalism is fine.
12. Consider the following possible electron arrangements for a p3 configuration:
A
B
C
D
Which configuration or configurations… (a) represent the ground state; (b)
represent excited states; (c) represent impossible states? In which state is
exchange energy maximized?
13. The figure below shows the values of IE1 for the first 20 elements. Give detailed
reasons for the observed trends in values. You should explain why specific
elements show deviations opposite the overall trend.
First ionization energy (kJ/mol)
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Atomic Number
14. Determine Z* for a valence electron in the second period of the periodic table (Li,
Be, … F, Ne). Place your answers in a table form. In a graph, plot Z* (y-axis)
against atomic number (x-axis). Compare your graph to a plot of atomic radius vs.
atomic number. Compare to first ionization vs. atomic number. Why would these
plots be similar or not similar?