Chapter 3: Ionic and Covalent Compounds

Chapter 3: Ionic and Covalent Compounds

Chapter 3: Ionic and Covalent Compounds

1. / Which is not an ionic compound?
A) KCl B) Ca(NO3)2 C) CBr4 D) AlBr3
Ans:C Difficulty:Easy
2. / Which is not a covalent compound?
A) / Br2
B) / NO2
C) / NH3
D) / NaNO2
E) / More than one of the compounds above is not a covalent compound.
Ans:D Difficulty:Easy
3. / In bonding, main group elements _____ to attain the electronic configuration of the noble gas closest to them in the periodic table.
A) / Gain electrons / C) / Share electrons
B) / Lose electrons / D) / Gain, lose, or share electrons
Ans:D Difficulty:Easy
4. / _____ are negatively charged ions that have _____ electrons than protons.
A) Anions, more B) Cations, more C) Anions, less D) Cations, less
Ans:A Difficulty:Medium
5. / Which statement concerning the ion Li+ is correct?
A) / Li+ has two total electrons.
B) / Li+ has an octet of electrons in its valence shell.
C) / Li+ is formed when a lithium atom gains one electron.
D) / Li+ is formed when a lithium atom gains one proton.
Ans:A Difficulty:Difficult
6. / What is the electron configuration of an F– ion?
A) 1s22s22p4 B) 1s22s22p5 C) 1s22s22p6 D) 1s22s22p63s1
Ans:C Difficulty:Difficult
7. / What is the ion symbol for an atom with twenty (20) protons and eighteen (18) electrons?
A) Ca B) Ca2+ C) Ar D) Ar2+ E) Ar2–
Ans:B Difficulty:Medium
8. / When forming ions, metals typically do which of the following?
A) / Lose electrons to form negatively charged ions
B) / Gain protons to form cations
C) / Gain electrons to form anions
D) / Lose electrons to form positively charged ions
Ans:D Difficulty:Easy
9. / What is the ion symbol for an atom with sixteen (16) protons and eighteen (18) electrons?
A) S2– B) S C) Ar D) Ar2+ E) Ar2–
Ans:A Difficulty:Medium
10. / How many protons and electrons are present in Co2+?
A) / 27 protons, 27 electrons / C) / 27 protons, 25 electrons
B) / 27 protons, 29 electrons / D) / 29 protons, 27 electrons
Ans:C Difficulty:Medium
11. / What is the symbol for the ion formed by magnesium?
A) Mg2– B) Mg3+ C) Mg2+ D) Mg4–
Ans:C Difficulty:Medium
12. / What is the charge of the ions formed by group 7A elements?
A) +1 B) +7 C) –1 D) –7
Ans:C Difficulty:Easy
13. / What is the ion symbol of the oxide ion?
A) O2– B) O22– C) O2 D) O2+
Ans:A Difficulty:Medium
14. / Which element has a variable charge?
A) Na B) Fe C) Al D) C
Ans:B Difficulty:Medium
15. / Which pair of elements will form an ionic compound?
A) / Sulfur and oxygen / C) / Iron and chlorine
B) / Copper and iron / D) / Bromine and oxygen
Ans:C Difficulty:Easy
16. / What is the formula for the ionic compound formed when potassium and bromine combine?
A) PBr B) KBr C) KBr2 D) K2Br
Ans:B Difficulty:Easy
17. / What is the formula for the ionic compound lithium oxide?
A) LiO B) LiO2 C) Li2O D) Li2O2
Ans:C Difficulty:Medium
18. / Which statement best explains the basis for the octet rule?
A) / Atoms are most stable when they have eight bonds.
B) / Atoms lose, gain, or share electrons to become a stable, noble gas.
C) / Atoms are most stable with eight protons in their nucleus.
D) / Atoms are most stable with eight electrons in their valence shell and the electron configuration of a noble gas.
Ans:D Difficulty:Difficult
19. / What is the formula for the ionic compound formed when magnesium and oxygen combine?
A) MgO B) MgO2 C) Mg2O D) Mg2O2
Ans:A Difficulty:Medium
20. / What is the formula for the ionic compound formed when aluminum and sulfur combine?
A) AlS B) Al2S3 C) AlS3 D) Al2S
Ans:B Difficulty:Difficult
21. / What is the proper name for CuCl?
A) / Copper chloride / C) / Copper (II) chloride
B) / Copper (I) chloride / D) / Copper monochloride
Ans:B Difficulty:Difficult
22. / What is the proper name for MgF2?
A) / Magnesium fluoride / C) / Magnesium (II) fluoride
B) / Magnesium (I) fluoride / D) / Magnesium difluoride
Ans:A Difficulty:Easy
23. / What is the name of the SO42– ion?
A) Sulfide ion B) Sulfate ion C) Sulfite ion D) Bisulfate ion
Ans:B Difficulty:Medium
24. / What is the chemical formula for the ionic compound calcium selenide?
A) Ca2Se2 B) CaSe C) CaSe2 D) Ca2Se
Ans:B Difficulty:Medium
25. / What is the chemical formula of tin (IV) cyanide?
A) Sn4CN B) SnCN4 C) Sn(CN)4 D) SnC4N4
Ans:C Difficulty:Difficult
26. / The formula for zinc acetate is _____.
A) ZnCH3CO2 B) Zn(CH3CO2)2 C) Zn(HCO3)2 D) Zn(HCl)8
Ans:B Difficulty:Difficult
27. / Which chemical formula is not correct?
A) Na2HCO3 B) NaNO3 C) Na2HPO4 D) Na2SO3
Ans:A Difficulty:Difficult
28. / Which chemical formula is correct?
A) Ag(CH3CO2)2 B) K2CN C) Mg(OH)2 D) MgHCO3
Ans:C Difficulty:Difficult
29. / An atom has the electron-dot symbol shown below. If this atom is a main group element, what charge will it form in its ionic state?

A) –1 B) +3 C) –5 D) –3
Ans:B Difficulty:Easy
30. / Which atom fits the electron-dot symbol shown below?

A) Li B) B C) N D) Na
Ans:B Difficulty:Medium
31. / If atoms with the electron-dot symbols shown below are combined, what is the formula of the ionic compound that is formed?

A) XY B) X2Y C) XY2 D) X2Y2 E) X3Y2
Ans:B Difficulty:Difficult
32. / If atoms with the electron-dot symbols shown below are combined, what is the formula of the ionic compound that is formed?

A) XY B) X2Y C) XY2 D) X2Y2 E) X3Y2
Ans:A Difficulty:Difficult
33. / What period 4 element forms an ion with a –1 charge?
A) Sulfur B) Bromine C) Iodine D) Rubidium
Ans:B Difficulty:Medium
34. / What is the name of the compound (NH4)2SO4?
A) / Ammonium sulfide / C) / Ammonia sulfoxide
B) / Ammonia sulfate / D) / Ammonium sulfate
Ans:D Difficulty:Difficult
35. / Which compound has the highest melting point?
A) KCl B) CH4 C) C6H12O6 D) H2O
Ans:A Difficulty:Medium
36. / What is the charge on the chromium ion in the ionic compound CrCl3?
A) +6 B) +3 C) –3 D) –6
Ans:B Difficulty:Difficult
37. / What is the formula for the ionic compound formed from the lead (II) ion and the carbonate ion?
A) Pb(CO3)2 B) PbCO3 C) Pb2CO3 D) PbCO4
Ans:B Difficulty:Difficult
38. / The correct name for AuI3 is
A) Silver iodide B) Gold iodide C) Gold (III) iodide D) Gold iodide (III)
Ans:C Difficulty:Medium
39. / What is the formula for chromous cyanide?
A) CrCN B) Cr(CN)2 C) Cr(CN)3 D) Cr2CN
Ans:B Difficulty:Difficult
40. / The diphosphate ion is a biologically important polyatomic ion. If the ionic compound calcium diphosphate has the formula Ca2P2O7, which correctly represents the ion symbol of the diphosphate ion?
A) P2O72– B) PO4– C) 2 PO46– D) P2O74–
Ans:D Difficulty:Difficult
41. / What is another name for an unshared pair of electrons in a covalent compound?
A) / Lone pair of electrons
B) / Nonbonded electron pair
C) / Bonding pair of electrons
D) / Lone pair of electrons or nonbonded electron pair
Ans:D Difficulty:Easy
42. / Which of the statements concerning chemical bonds is false?
A) / The sharing of electrons between two nonmetal atoms results in a covalent bond.
B) / The attraction between oppositely charged ions results in an ionic bond.
C) / The term nonpolar is used to describe a covalent bond in which electrons are not shared equally.
D) / A bond dipole is the separation of charge that results when atoms sharing electrons have different electronegativities.
Ans:C Difficulty:Medium
43. / How many covalent bonds are generally formed by atoms with five valence electrons?
A) 1 B) 2 C) 3 D) 4 E) 5
Ans:C Difficulty:Medium
44. / How many lone pairs of electrons are present in the Lewis structure of ammonia, NH3?
A) 0 B) 1 C) 2 D) 3 E) 4
Ans:B Difficulty:Easy
45. / How many nonbonded electron pairs are in the Lewis structure below?

A) 2 B) 4 C) 6 D) 8 E) 16
Ans:B Difficulty:Easy
46. / What is the Lewis structure for chloroethylene (C2H3Cl)?
A) /
B) /
C) /
D) /
Ans:C Difficulty:Difficult
47. / How many valence electrons are in a molecule of formaldehyde (CH2O)?
A) 16 B) 12 C) 10 D) 8
Ans:B Difficulty:Medium
48. / Predict the bond angles around the carbon atom in the structure of carbonic acid shown below. Don't forget to draw in lone pairs where needed to give octets.

A) 180° B) 120° C) 109.5° D) 90°
Ans:B Difficulty:Medium
49. / What is the molecular shape around the phosphorus atom in PH3?
A) Linear
B) Bent
C) Trigonal planar
D) Tetrahedral
E) Trigonal pyramidal
Ans:E Difficulty:Difficult
50. / What are the bond angles in a tetrahedral geometry?
A) 180° B) 120° C) 109.5° D) 90°
Ans:C Difficulty:Easy
51. / Aspartic acid is an amino acid used to synthesize proteins. How many lone pairs of electrons need to be added to complete the aspartic acid structure shown below?

A) 4 B) 6 C) 8 D) 9
Ans:D Difficulty:Medium
52. / Which of the following molecule(s) is(are) polar?
A) CO2 B) CH4 C) CBr4 D) CHBr3
Ans:D Difficulty:Difficult
53. / Rank the atoms Br, Cl, and K in order of increasing electronegativity.
A) K < Br < Cl B) Cl < Br < K C) Br < Cl < K D) K < Cl < Br
Ans:A Difficulty:Difficult
54. / Rank the atoms Br, Cl, and F in order of increasing electronegativity.
A) F < Br < Cl B) Cl < Br < F C) Br < Cl < F D) F < Cl < Br
Ans:C Difficulty:Medium
55. / Which atom has the lowest electronegativity?
A) Al B) S C) Se D) Rb
Ans:D Difficulty:Medium
56. / Which bond is the most polar?
A) C–N B) C–O C) C–C D) C–Cl E) C–F
Ans:E Difficulty:Difficult
57. / Which bond is the least polar?
A) C–N B) C–O C) C–C D) C–Cl E) C–F
Ans:C Difficulty:Easy
58. / Aspartic acid is an amino acid used to synthesize proteins. How many polar bonds are in the aspartic acid structure shown below?

A) 4 B) 6 C) 9 D) 12
Ans:C Difficulty:Difficult
59. / What is the correct chemical formula of selenium dioxide?
A) SO2 B) SeO2 C) Se2O D) OS2
Ans:B Difficulty:Easy
60. / Which bond has the polarity incorrectly labeled?
A) d+ H–Cl d– B) d+ O–C d– C) d+ Cl–F d– D) d– Cl–Br d+
Ans:B Difficulty:Medium
61. / Which is the correct Lewis structure for OBr–?
A) / / D) /
B) / / E) /
C) /
Ans:B Difficulty:Difficult
62. / Estimate the bond angles around the sulfur atom in the structure shown below.

A) 90° B) 109.5° C) 120° D) 180°
Ans:B Difficulty:Medium
63. / What is the molecular shape around the nitrogen atom in the structure shown below?

A) Linear
B) Bent
C) Trigonal planar
D) Tetrahedral
E) Trigonal pyramidal
Ans:B Difficulty:Difficult
64. / What is the molecular shape around the oxygen atom in the structure shown below?

A) Linear
B) Bent
C) Trigonal planar
D) Tetrahedral
E) Trigonal pyramidal
Ans:B Difficulty:Difficult
65. / Which element may have more than eight valence electrons around it when present in a covalent compound?
A) C B) B C) N D) P E) O
Ans:D Difficulty:Medium
66. / Which molecule or ion has only two resonance structures to describe its bonding?
A) CO32– B) NO3– C) HCO31– D) SO3
Ans:C Difficulty:Difficult
67. / Which of the following is classified as a group in the valence shell electron pair repulsion (VSEPR) theory?
A) / An atom
B) / A lone pair of electrons
C) / A valence electron
D) / Either an atom or a valence electron
E) / Either an atom or a lone pair of electrons
Ans:E Difficulty:Medium
68. / Which molecule's Lewis structure contains an atom that violates the octet rule?
A) H2O B) BeH2 C) PCl3 D) H2Se
Ans:B Difficulty:Difficult
69. / Which compound has the greatest number of valence electrons?
A) / H2S
B) / CH4
C) / NH3
D) / H2O
E) / All of the molecules above have the same number of valence electrons.
Ans:E Difficulty:Medium
70. / Which atom(s) in the structure below has(have) a partial negative charge (d–)?

A) Carbon
B) Fluorine
C) Hydrogen
D) Nitrogen
E) Nitrogen and fluorine
Ans:E Difficulty:Medium
71. / How many lone pairs of electrons need to be added to the Lewis structure of carbonic acid shown below?

A) 0 B) 3 C) 4 D) 6
Ans:D Difficulty:Medium
72. / What is the total number of bonding electrons in the structure below?

A) 5 B) 10 C) 20 D) 30
Ans:C Difficulty:Medium
73. / Which Lewis structure is incorrect?
A) /
B) /
C) /
D) /
Ans:B Difficulty:Difficult
74. / The Lewis structure shown below is not a valid Lewis structure. What statement best describes the error in the structure?