Chemistry 4510
Test I
Short Answer (5 points each)
1. Define atomic radii and describe the periodic trend for this physical characteristic.
2. Predict the shapes of the following molecules or ions: SF4, XeF4, SO423. Predict the hybridization of the central atom in the following molecules or ions:
CH3-, SOCl2, POCl3.
4. What is the coordination number of the cation and anion in the rock salt structure?
5. Calculate the effective nuclear charge on an electron in the 3s orbital for a gas phase
atom of magnesium.
6. Predict the point group for the following atoms or ions: N2O4, SO2Cl2, PCl5
7. Find and list all the symmetry elements for the following molecule: (CH3)2SiCl2
You may use drawings to explain the placement of each symmetry operator.
8. Write Lewis electron dot structures for: GeCl3-, CO32-, SO429. Calculate the formal charge for the central atom in each of the ions in question 8.
10. Can any of the ions in question 8 be drawn using resonance forms? If so, show all
possible resonance forms.
Discussion Questions (10 points each)
1. List and describe the four quantum numbers.
2. Explain the “breaks” in the graph of first ionization energy shown below.
3. Draw and completely label the Born-Haber cycle for NaCl.
4. Draw and completely label the molecular orbital diagram for HF.
5. Using band theory, explain how a n-type semiconductor works.