Open book and open notes.
October 18, 2001
1. Find the electron configuration for the following: Cr3+; Eu3+; S–; Ca+; Ni4+. Answer
2. Consider the melting point data for the natural forms of the second row elements given in the table below. Calculate Z* using Slater's rules for the outermost electron for each of these elements. Does Z* give a reasonable accounting of the trend in the melting point? Why or why not? Should melting point be considered a periodic property of atoms? Why or why not? Answer
Element |
Melting Point (oC) |
Na |
98 |
Mg |
650 |
Al |
660 |
Si |
1414 |
P |
44 |
S |
115 |
Cl |
–101.5 |
Ar |
–189 |
3. For the following chemical species, write the Lewis dot structure that minimizes formal charge, give the formal charge and oxidation number on each atom, show the structure including estimates of all bond angles accurate to ±2o, give the likely hybrid on the central atom, and give the point group: NH2Cl; SF3+; SOF4. Answer
4. The total representation for some set of objects in the D6 point group is given below. Find the irreducible representations for this set of objects. Answer
D6 |
E |
2C6 |
2C3 |
C2 |
3C2' |
3C2" |
|
6 |
–2 |
0 |
–2 |
0 |
0 |