Name: _________________________RICHLAND COLLEGECHEMISTRY 1411, SECTION 8250Exam 2 Review AnswersFALL 2010

MULTIPLE CHOICE QUESTIONS

1) The definitive distinction between ionic bonding and covalent bonding is thatA) ionic bonding involves a sharing of electrons and covalent bonding involves a transfer of electrons.B) ionic bonding involves a transfer of electrons and covalent bonding involves a sharing of electrons.C) ionic bonding requires two nonmetals and covalent bonding requires a metal and a nonmetal.D) covalent bonding requires two nonmetals and ionic bonding requires a metal and a nonmetal.

Answer: B

2) In which of the following sets do all species have the same number of electrons?A) Br-, Kr, Sr2+B) C, N3-, O2-C) Mg2+, Sr2+, Ba2+D) O, O2-, O2+Answer: A

3) In which set do all elements tend to form cations in binary ionic compounds?A) Li, B, OB) Mg, Cr, PbC) N, As, BiD) O, F, ClAnswer: B

4) The solid compound, Na2CO3, containsA) Na+, C4+, and O2- ions.B) Na+ ions and CO32-ions.

C) Na2+ and CO32- ions.D) Na2CO3 molecules.Answer: B

5) The gas Freon-11, CCl3F, contains

A) C4+, Cl-, and F- ions.B) C4+, Cl3-, and F- ions.

C) C4+ and Cl3F4- ions.D) CCl3F molecules.Answer: D

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6) Which of the compounds, C3H8, MgCl2, Zn(NO3)2, OCl2, are expected to exist as molecules?

A) only C3H8B) C3H8 and OCl2C) C3H8, Zn(NO3)2, and OCl2D) MgCl2 and Zn(NO3)2Answer: B

7) Which two ions have the same electron configuration in the ground state?A) Rb+ and Cs+B) Ba2+ and I-C) Se2+ and I-D) Fe2+ and Fe3+Answer: B

8) Arrange the ions N3-, O2-, Mg2+, Na+, and F- in order of increasing ionic radius, starting with the smallest first.A) Mg2+, Na+, F-, O2-, N3-B) N3-, Mg2+, O2-, Na+, F-C) N3-, O2-, Mg2+, F-, Na+D) N3-, O2-, F-, Na+, Mg2+Answer: A

9) Of the following, which element has the highest first ionization energy?A) AlB) ClC) NaD) PAnswer: B

10) List the elements Na, Ca, Rb, Cl, He in order of decreasing first ionization energy.A) He > Cl > Ca > Na > RbB) He > Na > Ca > Cl > RbC) He > Na > Cl > Ca > RbD) Rb > Ca > Cl > Na > HeAnswer: A

11) Which of the following atoms with the specified electronic configurations would have the lowest first ionization energy?A) [He]2s22p3B) [Ne]3s23p4C) [Xe]6s1D) [Xe]6s24f145d106p1Answer: C

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12) Which of the following represents the change in electronic configuration that is associated with the first ionization energy of magnesium?A) [Ne]3s13p1 → [Ne]3s1 + e-B) [Ne]3s2 → [Ne]3s13p1C) [Ne]3s2 → [Ne]3s1 + e-D) [Ne]3s2 + e- → [Ne]3s23p1Answer: C

13) Which period 3 element has successive first through seventh ionization energies (kJ/mol) : Ei1 = 578; Ei2 = 1,817; Ei3 = 2,745; Ei4 = 11,575; Ei5 = 14,830; Ei6 = 18,376; and Ei7 = 23,293?A) MgB) AlC) SD) ClAnswer: B

14) Which electron affinity process would liberate the most energy?A) [He] 2s2 + e- → [He] 2s2 2p1B) [He] 2s2 2p2 + e- → [He] 2s2 2p3C) [He] 2s2 2p3 + e- → [He] 2s2 2p4D) [He] 2s2 2p6 + e- → [He] 2s2 2p6 3s1Answer: B

15) Which element has the least favorable (least negative) electron affinity?A) BB) CC) ND) OAnswer: C

16) What is the general trend in ionization energy and electron affinity values?A) Both decrease as one traverses a period from left to right and both decrease as one descends a group.B) Both decrease as one traverses a period from left to right and both increase as one descends a group.C) Both increase as one traverses a period from left to right and both decrease as one descends a group.D) Both increase as one traverses a period from left to right and both increase as one descends a group.Answer: C

17) An element that has the valence electron configuration 3s23p3 belongs to which period and group?A) period 3; group 3AB) period 3; group 5AC) period 4; group 3AD) period 4; group 5AAnswer: B

18) An element M reacts with chlorine to form MCl2, with oxygen to form MO, and with nitrogen to form

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M3N2. The most likely candidate for the element isA) LiB) MgC) AlD) SiAnswer: B

19) Which of the following ionic compounds would be expected to have the highest lattice energy?A) LiClB) NaClC) KClD) RbClAnswer: A

20) Which ionic compound would be expected to have the highest lattice energy?A) Na2OB) MgOC) Al2O3D) CO2Answer: C

21) What are the names of the ions Ba2+, Sn2+, and Se2-?A) barium, tin, and seleniumB) barium, tin(II), and selenideC) barium(II), tin(II), and selenium(II-)D) barous, stannous, and selenideAnswer: B

22) What is the charge on the Cr in the ionic compound Cr2O3?A) 2-B) 1+C) 2+D) 3+Answer: D

23) Li2S is namedA) lithium disulfide.B) lithium sulfide.C) lithium(II) sulfide.D) lithium sulfur.Answer: B

24) The chemical formula for calcium nitride isA) Ca(NO3)2.B) Ca(NO2)2.

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C) Ca3N2.D) CaN2.Answer: C

25) KH2PO4 isA) hydropotassium phosphate.B) potassium dihydrogen phosphate.C) potassium diphosphate.D) potassium hydrogen(II) phosphate.Answer: B

26) The compound, Cu(ClO3)2, is namedA) copper chlorate(II).B) copper(I) chlorate.C) copper(I) chlorate(II).D) copper(II) chlorate.Answer: D

27) An incorrect statement about the alkaline earth metals is:A) Melting points generally decrease as one descends the group.B) Densities are less than those of the corresponding alkali elements of the same period.C) Ionic radii of the M2+ ion increases as one descends the group.D) The first ionization energy is less than that of the second ionization energy.Answer: B

28) Predict the product(s) when the reactants Be(s) + Br2(l) are mixed.A) BeBr(s)B) BeBr2(s)C) Be2Br(s)D) BeBr3(s)Answer: B

29) Which of the following statements about helium is inconsistent with its chemistry?A) A helium oxygen mixture is used as a deep-sea diving gas instead of compressed air.B) In its liquid form it is used as a cryogenic coolant for superconductors.C) It is one of the more reactive elements of its group.D) Its melting point is -272.2°C and its boiling point is -268.9°C.Answer: C

In the following drawings, shaded spheres represent cations and unshaded spheres represent anions.

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30) Which drawing represents the ionic compound Mg3(PO4)2?A) drawing (a)B) drawing (b)C) drawing (c)D) drawing (d)Answer: D

31) Which drawing represents the ionic compound Na2CO3?A) drawing (a)B) drawing (b)C) drawing (c)D) drawing (d)Answer: B

32) Which drawing represents the ionic compound CaCl2?A) drawing (a)B) drawing (b)C) drawing (c)D) drawing (d)Answer: C

33) Which bond should have the highest bond dissociation energy?A) N–NB) N=NC) N≡ND) All three bonds should have about the same dissociation energy.Answer: C

34) Compound A is a solid with a melting point of 125°C, and compound B is a gas at 25°C and one atmosphere pressure. Based on these data, one would expectA) both compounds to be covalent.B) compound A to be ionic and compound B to be covalent.C) compound A to be covalent and compound B to be ionic.D) both compounds to be ionic.Answer: A

35) Of the following elements, which has the lowest electronegativity?A) MgB) Cl

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C) CaD) BrAnswer: C

36) The compound ICl containsA) ionic bonds.B) nonpolar covalent bonds.C) polar covalent bonds, with partial negative charges on the Cl atoms.D) polar covalent bonds, with partial negative charges on the I atoms.Answer: C

37) Which molecule contains the most polar bonds?A) CF4B) CO2C) CN-

D) CH4Answer: A

38) The phosphorus atom in PCl3 would be expected to have aA) partial positive (δ+) charge.B) partial negative (δ-) charge.C) 3+ charge.D) 3- charge.Answer: A

39) Based on the indicated electronegativities, arrange the following in order of increasing ionic character: CsBr, LaBr3, PBr3, MgBr2.

A) CsBr, LaBr3, MgBr2, PBr3B) CsBr, MgBr2, PBr3, LaBr3C) PBr3, LaBr3, MgBr2, CsBrD) PBr3, MgBr2, LaBr3, CsBrAnswer: D

40) Which molecule contains a triple bond?A) F2B) O3C) HCN

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D) H2COAnswer: C

41) Which of the following contains an atom that does not obey the octet rule?A) KBrB) CO2C) ClF3D) IClAnswer: C

42) How many lone pairs of electrons are on the Xe atom in XeF6?A) 0B) 1C) 2D) 3Answer: B

43) Based on formal charge considerations, the electron-dot structure of CO32– ion hasA) two resonance structures involving two single bonds and one double bond.B) two resonance structures involving one single bond and two double bonds.C) three resonance structures involving two single bonds and one double bond.D) three resonance structures involving one single bond and two double bonds.Answer: C

44) Assign formal charges to each atom in the resonance form for SOCl2 given below.

A) 0 for Cl, 0 for S, and 0 for OB) 0 for Cl, +1 for S, and -1 for OC) -1 for Cl, +4 for S, and -2 for OD) -1 for Cl, -2 for S, and -2 for OAnswer: B

45) Which electron dot structure for OCN- has a formal charge of -1 on the most electronegative atom?

A) [:N. .

= C =O. .

:] –

B) [: N ≡ C –O. .

. .

:] –

C) [:N. .

. .

– C ≡ O :] –

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D) [:N. .

. .

– O ≡ C :] –Answer: B

46) What is the molecular geometry of BrF4-?A) seesawB) square planarC) square pyramidalD) tetrahedralAnswer: B

47) What is the molecular geometry of TeCl4?A) seesawB) square planarC) square pyramidalD) tetrahedralAnswer: A

48) Arrange in order from the smallest to the largest bond angle: CH3+, NF3, NH4+, XeF4.

A) CH3+, NF3, NH4+, XeF4B) NF3, NH4+, XeF4, CH3+

C) XeF4, NH4+, NF3, CH3+

D) XeF4, NF3, NH4+, CH3+

Answer: D

49) What orbital hybridization is expected for the central atom in a molecule with a trigonal planar geometry?A) spB) sp2C) sp3D) None of the aboveAnswer: B

50) The orbital hybridization on the carbon atom in HCN isA) sp.B) sp2.C) sp3.D) none of the above.Answer: A

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