CHEM 1411. Chapter 8.Molecular Geometry and Bonding Theories (Homework) W Multiple Choice Identify the choice that best completes the statement or answers the question. ____ 1. The electrons in the outer shell of an atom are involved in bonding. Another name for the outer shell is ____. a. valence shell b. VSEPR shell c. bonding shell d. hybridized shell e. Lewis shell ____ 2. What angle(s) are associated with a central atom that has trigonal bipyramidal electronic geometry? a. 90 and 180 b. 120 and 180 c. 120 d. 90 and 120 e. 109.5 ____ 3. Which one of the following molecules is polar? a. P4 b. H2O c. CO2 d. Cl2 e. N2 ____ 4. The ONO bond angles associated with the nitrate ion, NO3 , are all 120. The hybridization at the nitrogen atom is ____. a. sp3d b. sp3 c. sp3d2 d. sp e. sp2 ____ 5. Which of the following statements about polar molecules is false? a. A molecule with polar bonds can be polar. b. A molecule with 120 bond angles can be polar. c. A molecule with only nonpolar bonds can be polar. d. A molecule with polar bonds can be nonpolar. e. A molecule with 180 bond angles can be polar. ____ 6. Which one of the following molecules has sp hybridization at the central atom? a. BF3 b. SeF6 c. PF5 d. CF4 e. BeF2 ____ 7. Which of the following molecules has 120 bond angles? 1 CHEM 1411. Chapter 8.Molecular Geometry and Bonding Theories (Homework) W a. BCl3 b. H2S c. BeI2 d. NF3 e. CH4 ____ 8. Which of the following molecules has 120 bond angles? a. CF4 b. BI3 c. H2O d. BF4 + e. NH4 ____ 9. Which of the following is a false statement about BF3? a. The B atom does not satisfy the octet rule. b. BF3 has trigonal pyramidal electronic geometry. c. All three bond angles in BF3 are 120. d. BF3 has trigonal planar molecular geometry. e. Although the electronegativity difference between B and F is large (2.0 units), BF3 is a covalent compound. ____ 10. Which response contains all the characteristics listed that should apply to silicon tetrafluoride, SiF4, and no other characteristics? I. tetrahedral II. 120 bond angles III. sp hybridized at C IV. polar molecule V. one unshared pair of electrons on Si a. II and III b. I c. I and V d. II, IV, and V e. none of these ____ 11. Molecules such as NF3 are best described by assuming what kind of hybridization at the central atom? a. sp b. sp3d2 c. sp3d d. sp3 e. sp2 ____ 12. Four of the following statements about the ammonia molecule, NH3, are correct. One is not. Which one? a. The ammonia molecule is tetrahedral. b. The bond dipoles re-enforce the effect of the unshared pair of electrons on the nitrogen atom. c. The bond angles in the ammonia molecule are less than 109. d. Since nitrogen is more electronegative than hydrogen, the bond dipoles are directed toward the nitrogen atoms. e. The nitrogen atom can be described as utilizing sp3 hybrid orbitals in the ammonia 2 CHEM 1411. Chapter 8.Molecular Geometry and Bonding Theories (Homework) W molecule. ____ 13. Four of the following statements about the ammonia molecule, NH3, and the nitrogen trifluoride molecule, NF3, are correct. One is not. Which one? a. The nitrogen atom can be described as utilizing sp3 hybrid orbitals in the nitrogen trifluoride molecule. b. The bond dipoles in NF3 are directed toward the more electronegative fluorine atoms. c. Fluorine atoms are larger than hydrogen atoms, and therefore the bond angles in NF3 are greater than in NH3. d. The bond dipoles in NF3 oppose the effect of the unshared pair of electrons. e. The NH3 molecule is more polar than the NF3 molecule. ____ 14. What is the hybridization at the central atom (P) of PF3Cl2? a. sp b. sp3d2 c. sp3 d. sp3d e. sp2 ____ 15. How many unshared electrons are there in the highest energy level of phosphorus in the covalent compound PF5? (HINT: Draw Lewis dot formula.) a. five b. two c. three d. none e. eight ____ 16. Which of the following statements about AsF5 is false? a. As has one lone pair. b. As is sp3d hybridized. c. Bonding angles are 90, 120 or 180. d. The molecular geometry is trigonal bipyramidal. e. The electronic geometry is trigonal bipyramidal. ____ 17. Which response includes all the polar molecules listed and no nonpolar molecules? BCl3, AsF5, NF3, H2S a. BCl3, NF3 b. AsF5, NF3, H2S c. BCl3, AsF5 d. BCl3, H2S e. NF3, H2S ____ 18. Which of the following statements about molecules with octahedral electronic geometry is false? a. If there are two lone pairs of electrons on the central atom they will be 180 apart. b. The molecular geometry is square planar if there are two lone pairs of electrons on the central atom. c. They are sp3d2 hybridized. d. The bond angles are 90, 120 or 180. e. Octahedral geometry is symmetrical. 3 CHEM 1411. Chapter 8.Molecular Geometry and Bonding Theories (Homework) W ____ 19. Which of the following statements about multiple bonds is true? a. A double bond consists of two sigma bonds. b. A sigma bond results from the side-on overlap of p atomic orbitals. c. sp2 hybridization in carbon is associated with one double bond and two single bonds. d. sp3 hybridization in carbon is associated with one double bond and two single bonds. e. A pi bond results from the head-on overlap of p atomic orbitals. ____ 20. How many sigma ()bonds and how many pi () bonds does the ethene molecule contain? a. 5 , 1 b. 4 , 2 c. 5 , 2 d. 5 , 0 e. 8 , 2 ____ 21. What is the hybridization of a carbon atom involved in a double bond? a. sp3d b. sp c. sp2 d. sp3d2 e. sp3 ____ 22. How many sigma () bonds and how many pi () bonds does the acetylene molecule contain? a. 3 and 2 b. 2 and 2 c. 3 and 1 d. 2 and 3 e. 5 and 1 ____ 23. What is the hybridization of a carbon atom involved in a triple bond? a. sp3d b. sp3 c. sp d. sp2 e. sp3d2 ____ 24. What is the geometry of a carbon atom involved in a triple bond? a. tetrahedral b. octahedral c. trigonal planar d. trigonal bipyramidal e. linear ____ 25. Which of the following responses contains all of the true statements for ethyne? I. The ethyne molecule has a double bond between its 2 carbon atoms. II. The ethyne molecule has a triple bond between its 2 carbon atoms. 4 CHEM 1411. Chapter 8.Molecular Geometry and Bonding Theories (Homework) W III. One pi bond is formed between the 2 carbon atoms by head-on overlap of the sp hybrid orbitals. IV. One sigma bond is formed between the 2 carbon atoms by head-on overlap of the sp2 hybrid orbitals. V. The ethyne molecule is linear. a. I and III b. II and IV c. I and IV d. II and V e. II and III ____ 26. Choose the species that is incorrectly matched with the electronic geometry about the central atom. Ion / Electronic Geometry a. BrO4 / tetrahedral b. NO2 / trigonal planar 2 c. SO3 / pyramidal d. ClO3 / tetrahedral e. ClO4 / tetrahedral ____ 27. Which molecule is incorrectly matched with the molecular geometry? Molecule / Molecular Geometry a. CCl4 / tetrahedral b. PH3 / pyramidal c. SO2 / linear d. BeCl2 / linear e. BBr3 / trigonal planar ____ 28. Which molecule is incorrectly matched with the molecular geometry? Molecule / Molecular Geometry a. SbH3 / pyramidal b. SF4 / tetrahedral c. CCl4 / tetrahedral d. SO3 / pyramidal e. SeF6 / octahedral ____ 29. Which molecule is incorrectly matched with the molecular geometry? Molecule / Molecular Geometry a. H2S / linear b. BCl3 / trigonal planar c. SF6 / octahedral d. AsH3 / pyramidal e. AsF5 / trigonal bipyramidal ____ 30. Which of the following molecules does not have tetrahedral electronic geometry? a. ClO3 5 CHEM 1411. Chapter 8.Molecular Geometry and Bonding Theories (Homework) W b. CCl2F2 2 c. SO3 d. ClO2 e. SF4 3 ____ 31. Which, if any, of the compounds listed are not sp hybridized at the central atom? I. CF4 II. H2O III. SiF4 IV. CHCl3 V. NH3 a. III and IV b. I, II, and III c. II, IV, and V d. III and V e. all are sp3 hybridized 3 ____ 32. Which, if any, of the compounds listed are not sp d hybridized at the central atom? I. BF3 II. AsI5 III. SF4 IV. BrF5 V. XeF4 a. III and IV b. I, II, and III c. I, IV, and V d. III and V e. all are sp3d hybridized ____ 33. Which species is incorrectly matched with bond angles? Molecule / Bond Angles a. SeO4 / 109.5 b. NH3 / 107 c. SnCl4 / 90, 120 (and 180) d. ClO3 / slightly less than 109 e. HCl / 180 ____ 34. What is the bond angle in a trigonal planar molecule or ion? a. 109° b. 72° c. 180° d. 120° e. 90° ____ 35. How many sigma and pi bonds are in the molecule pictured below? 6 CHEM 1411. Chapter 8.Molecular Geometry and Bonding Theories (Homework) W a. eleven sigma bonds and two pie bonds b. five sigma bonds and eleven pie bonds c. thirteen sigma bonds and one pi bond d. thirteen sigma bonds and two pie bonds e. eleven sigma bonds and five pie bonds Use the following Lewis structure for acetic acid to answer the following questions: ____ 36.