CLEARLY SHOW THE METHOD USED AND THE STEPS INVOLVED IN ARRIVING AT YOUR ANSWERS. It is to your advantaged to do this, since you may obtain partial credit if you do and will receive little or no credit if you do not. 1. The species represented below all have the same number of chlorine atoms attached to the central atom. GeCl4 SeCl4 ICl4-­‐ ICl4+ a. Draw the Lewis structure (electron-­‐dot diagram) of each of the four species. Show all valence electrons in your structures. b. On the basis of the Lewis structures drawn in part (a), answer the following questions about the particular species indicated. i. What is the Cl-­‐Ge-­‐Cl bond angle in GeCl4? ii. Is SeCl4 polar? Explain. iii. What is the hybridization of the I atom in ICl4-­‐ iv. What is the geometric shape formed by the atoms in ICl4+? 2. Answer the following questions that relate to chemical bonding. a. Draw the complete Lewis structure (electron-­‐dot diagram) for each of the three molecules listed below. i. CF4 ii. PF5 iii. SF4 b. On the basis of the Lewis structures draw above, answer the following questions about the particular molecule indicated. i. What is the F-­‐C-­‐F bond angle in CF4? ii. What is the hybridization of the valence orbitals of P in PF5? iii. What is the geometric shape formed by the atoms in SF4? c. Two Lewis structures can be drawn for the OPF3 molecule, as shown below. i. How many sigma bonds and how many pi bonds are in Structure 1? ii. Which of the two structures best represents a molecule of OPF3? Justify your answer in terms of formal charge. Page 1 of 2 3. Use principles of atomic structure, bonding and intermolecular forces to answer the following questions. Your responses must include specific information about all substances referred to in each part. a. Draw a complete Lewis electron-­‐dot structure for the CS2 molecule. Include all valence electrons in your structure. b. The carbon-­‐to-­‐sulfur bond length in CS2 is 160 picometers. Is the carbon-­‐to-­‐selenium bond length in CSe2 expected to be greater than, less than, or equal to this value? Justify your answer. c. The bond energy of the carbon-­‐to-­‐sulfur bond in CS2 is 577 kJ mol-­‐1. Is the bond energy of the carbon-­‐to-­‐selenium bond in CSe2 expected to be greater than, less than, or equal to this value? Justify your answer. d. The complete structural formulas of propane, C3H8, and methanoic acid, HCOOH, are shown above. In the table below, write the type(s) of intermolecular attractive force(s) that occur in each substance. e. Use principles of intermolecular attractive forces to explain why methanoic acid has a higher boiling point than propane. Page 2 of 2