Multiple Choice Identify the choice that best completes the statement or answers the question.

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1 Covalent Practice CP November 2015 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Bromine, atomic number 35, belongs to Group 17. How many electrons does bromine have in its outermost energy level? a. 7 c. 18 b. 17 d The first member of the noble gas family, whose highest energy level consists of an octet of electrons, is a. helium. c. neon. b. argon. d. krypton. 3. The energy required to remove an electron from an atom is the atom's a. electron affinity. c. electronegativity. b. electron energy. d. ionization energy. 4. A measure of the ability of an atom in a chemical compound to attract electrons is called a. electron affinity. c. electronegativity. b. electron configuration. d. ionization potential. 5. The element that has the greatest electronegativity is a. oxygen. c. chlorine. b. sodium. d. fluorine. 6. One-half the distance between the nuclei of identical atoms that are bonded together is called the a. atomic radius. c. atomic volume. b. atomic diameter. d. electron cloud. 7. In a row in the periodic table, as the atomic number increases, the atomic radius generally a. decreases. c. increases. b. remains constant. d. becomes unmeasurable. 8. Within a group of elements, as the atomic number increases, the atomic radius a. increases. c. decreases regularly. b. remains approximately constant. d. decreases, but not regularly. 9. In the alkaline-earth group, atoms with the smallest radii a. are the most reactive. c. are all gases. b. have the largest volume. d. have the highest ionization energies.

2 10. As the atomic number of the metals of Group 1 increases, the ionic radius a. increases. c. remains the same. b. decreases. d. cannot be determined. 11. Across a period in the periodic table, atomic radii a. gradually decrease. b. gradually decrease, then sharply increase. c. gradually increase. d. gradually increase, then sharply decrease. 12. The ionization energies for removing successive electrons from sodium are 496 kj/mol, 4562 kj/mol, 6912 kj/mol, and 9544 kj/mol. The great jump in ionization energy after the first electron is removed indicates that a. sodium has four or five electrons. b. the atomic radius has increased. c. a d-electron has been removed. d. the noble gas configuration has been reached. 13. Which is the best reason that the atomic radius generally increases with atomic number in each group of elements? a. The nuclear charge increases. c. The number of energy levels increases. b. The number of neutrons d. A new octet forms. increases. 14. The ionization energies required to remove successive electrons from one mole of calcium atoms are 590 kj/mol, 1145 kj/mol, 4912 kj/mol, and 6474 kj/mol. The most common ion of calcium is probably a. Ca +. c. Ca 3+. b. Ca 2+. d. Ca When chemical compounds form, valence electrons are those that may be a. lost only. c. shared only. b. gained only. d. lost, gained, or shared. 16. The electrons involved in the formation of a chemical bond are called a. dipoles. c. Lewis electrons. b. s electrons. d. valence electrons. 17. The chemical bond formed when two atoms share electrons is called a(n) a. ionic bond. c. Lewis structure. b. orbital bond. d. covalent bond. 18. If two covalently bonded atoms are identical, the bond is a. nonpolar covalent. c. nonionic. b. polar covalent. d. coordinate covalent.

3 19. When atoms share electrons, the electrical attraction of an atom for the electrons is called the atom's a. electron affinity. c. resonance. b. electronegativity. d. hybridization. 20. If the atoms that share electrons have an unequal attraction for the electrons, the bond is called a. nonpolar. c. ionic. b. polar. d. dipolar. 21. The B F bond in BF 3 (electronegativity for B is 2.0; electronegativity for F is 4.0) is a. polar covalent. c. nonpolar covalent. b. ionic. d. pure covalent. 22. In which of these compounds is the bond between the atoms NOT a nonpolar covalent bond? a. Cl 2 c. HCl b. H 2 d. O Which of the following is NOT an example of a molecular formula? a. H 2 O c. NH 3 b. B d. O In drawing a Lewis structure, the central atom is usually the a. atom with the greatest mass. c. atom with the fewest electrons. b. atom with the highest atomic d. least electronegative atom. number. 25. After drawing a Lewis structure, one should a. determine the number of each type of atom in the molecule. b. add unshared pairs of electrons around nonmetal atoms. c. determine the total number of valence electrons in each atom. d. determine the electronegativity of each atom. 26. The substance whose Lewis structure shows three covalent bonds is a. H 2 O. c. NH 3. b. CH 2 Cl 2. d. CCl How many double bonds are in the Lewis structure for hydrogen fluoride, HF? a. none c. two b. one d. three 28. How many electrons must be shown in the Lewis structure of the hydroxide ion, OH? a. 1 c. 9 b. 8 d. 10

4 29. Referencing the choices above, what is the correct Lewis structure for HCl? a. A c. C b. B d. D 30. Referencing the choices above, what is the Lewis structure for carbon tetraiodide, which contains one carbon atom and four iodine atoms? a. A c. C b. B d. D 31. Bonding in molecules or ions that cannot be correctly represented by a single Lewis structure is a. covalent bonding. c. single bonding. b. resonance. d. double bonding. 32. To indicate resonance, a is placed between a molecule's resonance structures. a. double-headed arrow c. series of dots b. single-headed arrow d. Lewis structure 33. The chemical formula for water, a covalent compound, is H 2 O. This formula is an example of a(n) a. formula unit. c. ionic formula. b. Lewis structure. d. molecular formula. 34. Compared with nonmetals, the number of valence electrons in metals is generally a. smaller. c. about the same. b. greater. d. almost triple that of nonmetals. 35. In metals, the valence electrons a. are attached to particular positive c. are immobile. ions. b. are shared by all of the atoms. d. form covalent bonds. 36. In the electron-sea model of a metallic bond,

5 a. electrons are stationary. b. electrons are bonded to particular positive ions. c. some electrons are valence electrons and some are not. d. mobile electrons are shared by all the atoms. 37. The electron-sea model of bonding represents a. covalent bonding. c. ionic bonding. b. metallic bonding. d. hydrogen bonding. 38. VSEPR theory is a model for predicting a. the strength of metallic bonds. c. lattice energy values. b. the shape of molecules. d. ionization energy. 39. According to VSEPR theory, the structure of the ammonia molecule, NH 3, is a. linear. c. pyramidal. b. bent. d. tetrahedral. 40. Use VSEPR theory to predict the shape of the hydrogen chloride molecule, HCl. b. linear d. trigonal planar 41. Use VSEPR theory to predict the shape of the phosporus trihydride molecule. a. tetrahedral c. trigonal pyramidal b. linear d. bent 42. Use VSEPR theory to predict the shape of the carbon tetraiodide molecule, CI 4. b. linear d. trigonal planar 43. Use VSEPR theory to predict the shape of the hydrogen sulfide molecule, H 2 S. b. linear d. octahedral 44. Use VSEPR theory to predict the shape of carbon dioxide, CO 2. b. linear d. octahedral 45. The following molecules contain polar bonds. The only polar molecule is a. CCl 4. c. NH 3. b. CO 2. d. CH The following molecules contain polar bonds. The only nonpolar molecule is a. HCl. c. CO 2. b. H 2 O. d. NH A polar molecule contains a. ions. b. a region of positive charge and a region of negative charge. c. only London forces.

6 d. no bonds. 48. A molecule of hydrogen chloride is polar because a. it is composed of ions. b. it is magnetic. c. it contains metallic bonds. d. the chlorine attracts the shared electrons more strongly than does the hydrogen atom. 49. How many atoms of fluorine are present in a molecule of carbon tetrafluoride, CF 4? a. 1 c. 4 b. 2 d Which formula does NOT represent a molecule? a. H 2 O ( c. CO 2 b. NH 3 d. NaCl 51. Fluorine belongs to group 7A. How many covalent bonds are formed between two fluorine atoms? a. 1 c. 3 b. 2 d If the electronegativity of H is 2.20 and of Cl is 3.55, which type of bond is formed between H and Cl, when they form hydrogen chloride? a. Ionic c. Covalent b. Polar ionic d. Polar covalent 53. A covalent bond results when are shared. a. ions c. electrons b. Lewis structures d. dipoles 54. To draw a Lewis structure, one must know the a. number of valence electrons in each atom. b. atomic mass of each atom. c. bond length of each atom. d. ionization energy of each atom. 55. Name the compound CF 4. a. calcium fluoride c. carbon tetrafluoride b. carbon fluoride d. monocarbon quadrafluoride 56. Name the compound SiO 2. a. silver oxide c. silicon dioxide b. silicon oxide d. monosilicon dioxide 57. Name the compound N 2 O 4. a. sodium tetroxide c. nitrous oxide

7 b. dinitrogen tetroxide d. binitrogen oxide 58. Name the compound SO 3. a. sulfur trioxide c. selenium trioxide b. silver trioxide d. sodium trioxide 59. Name the compound N 2 O 5. a. dinickel pentoxide c. neon oxide b. dinitrogen pentoxide d. nitric oxide 60. Which compound's name includes the Greek numerical prefixes di- and tri-? a. Fe 2 O 3 c. N 2 O 3 b. Ca 3 (PO 4 ) 2 d. Al 2 S Name the compound N 2 O 3. a. dinitrogen oxide c. nitric oxide b. nitrogen trioxide d. dinitrogen trioxide 62. What is the formula for nitrogen monoxide? a. N 2 O c. NO b. NOO d. N 2 O What is the formula for silicon dioxide? a. SO 2 c. Si 2 O b. SiO 2 d. S 2 O 64. What is the formula for nitrogen trifluoride? a. NiF 3 c. N 3 F b. NF 3 d. Ni 3 F 65. What is the formula for dinitrogen trioxide? a. Ni 2 O 3 c. N 2 O 6 b. NO 3 d. N 2 O What is the formula for sulfur dichloride? a. NaCl 2 c. S 2 Cl b. SCl 2 d. S 2 Cl What is the formula for diphosphorous pentoxide? a. P 2 PeO 5 c. P 2 O 4 b. PO 5 d. P 2 O What is the formula for carbon disulfide? a. CaS 2 c. S 2 C b. CS 2 d. SC 2