Chapter 20 1 What is the characteristic outer electron configuration for

Chemistry, 7e (McMurry/Fay)

Chapter 20 Transition Elements and Coordination Chemistry

20.1 Multiple-Choice Questions

1) The number of transition series is

A) one

B) two

C) four

D) seven

2) In which blocks of the periodic table are the transition series and inner transition series elements

found?

A) d, p

B) d, f

C) s, d

D) s, p

3) What is the characteristic outer electron configuration for transition elements?

A) (n – 1)d10–xns2

B) (n)d10-xns2

C) (n + 1)d10-xns1

D) (n – 1)d10-x(n + 1)s2

2

4) What is the ground-state electron configuration for the element cobalt (Z = 27)?

A) [Ar] 4s2 3d7

B) [Ar] 3d9

C) [Ar] 4s2 4p6 5s1

D) [Ar] 3d7

5) What is the ground-state electron configuration for the element chromium (Z = 24)?

A) [Ne] 4s2 3d4

B) [Ar] 4s2 3d4

C) [Ar] 4s1 3d5

D) [Ar] 3d6

6) What is the ground-state electron configuration for Cr in Cr2O72-?

A) [Ar] 4s1 3d5

B) [Ar] 4s2 3d6

C) [Ar] 3d4

D) [Ar] 3d0

7) What is the ground-state electron configuration for Co2+ (Z = 27)?

A) [Ar] 4s2 3d9

B) [Ar] 4s2 3d5

C) [Ar] 3d7

D) [Ar] 4s1 3d6

8) Which transition metal has the anomalous ground-state electron configuration: [Kr] 4d10?

A) Rh

B) Pd

C) Ag

D) Cd

9) Element M has the valence electron configuration 3d6 4s2. What is the valence electron configuration of

the M3+ ion?

A) 3d5

B) 3d3 4s2

C) 3d4 4s1

D) 3d9 4s2

10) How many d electrons are there in MnO4–?

A) 0

B) 1

C) 2

D) 3

11) What is the d orbital-filling diagram for Fe3+ (Z = 26)?

A) (A)

B) (B)

C) (C)

D) (D)

12) Which of the following statements best explains why transition metals lose electrons from s orbitals

before d orbitals?

A) Electrons from s orbitals are lower in energy than d orbitals.

B) The d orbitals experience a greater drop in energy when electrons are removed.

C) Electrons from d orbitals are less shielded from the nucleus than electrons in s orbitals.

D) Electrons in s orbitals are paired.

13) Transition series elements are all

A) gases.

B) metals.

C) nonmetals.

D) semimetals.

5

14) For transition elements, which of the following occurs as the effective nuclear charge increases?

A) The atomic radius increases.

B) The density increases.

C) Both the atomic radius and the density increase.

D) The atomic radius decreases and the density increases.

15) Though we would expect an increase in atomic radii going down a group from the second to the third

transition series of elements, the actual radii are nearly identical. The term commonly used to describe

this phenomenon is the

A) atomic disparity.

B) effective nuclear charge.

C) lanthanide contraction.

D) transition default.

16) What oxidation state(s) is(are) exhibited by all first row transition elements except scandium?

A) +2

B) +3

C) +2 and +3

D) +2, +3 and +4

17) What statement is most inconsistent with the chemistry of transition elements?

A) Bromide, chloride and iodide stabilize the higher oxidation states of the transition elements.

B) Early transition metal ions with the metal in its lowest oxidation state are good reducing agents.

C) Ions that have transition metal in their highest oxidation state tend to be good oxidizing agents.

D) The stability of the higher oxidation states increases down a periodic group.

18) What is the strongest oxidizing agent of the following set: VCl2, CrCl3, KMnO4, KReO4?

6

A) VCl2

B) CrCl3

C) KMnO4

D) KReO4

19) What is the strongest oxidizing agent of the following set: MnCl2, Mn(OH)3, MnO2, KMnO4?

A) MnCl2

B) Mn(OH)3

C) MnO2

D) KMnO4

20) Which of the following ions has the greater effective nuclear charge?

A) V3+

B) Cr3+

C) Fe3+

D) Co3+

21) Which of the following ions should be the strongest reducing agent?

A) V3+

B) Cr3+

C) Fe3+

D) Co3+

22) What chemical equation represents the best method for obtaining pure chromium?

A) FeCr2O4(s) + 4 C(s) + heat → Fe(s) + 2 Cr(s) + 4 CO(g)

7

B) Cr2O3(s) + 2 Al(s) + heat → 2 Cr(s) + Al2O3(s)

C) Cr2O3(s) + 2 Fe(s) + heat → Fe2O3(s) + 2 Cr(s)

D) Cr2+(aq) + H2(g) → Cr(s) + 2 H+(aq)

23) Which is not a characteristic reaction of chromium metal or chromium(II) ion?

A) Cr(s) + 2 H+(aq) → Cr2+(aq) + H2(g)

B) 4 Cr2+(aq) + O2(g) + 4 H+(aq) → 4 Cr3+(aq) + 2 H2O(l)

C) Cr(OH)2(s) + 2 H3O+(aq) → Cr2+(aq) + 4 H2O(l)

D) Cr(OH)2(s) + OH–(aq) → Cr(OH)3–(aq)

24) Which of the following chromium species is the strongest acid?

A) Cr(OH)2

B) Cr(OH)3

C) CrO2(OH)2

D) CrO42-

25) Which chromium species exists only under acidic conditions?

A) Cr(OH)2

B) Cr(OH)4–

C) CrO42-

D) Cr2O72-

26) Which is the strongest oxidizing agent under acidic conditions?

A) Cr2+

B) Cr3+

C) CrO42-

D) Cr2O72-

27) In the two half-reactions shown below, which chromium species is the strongest oxidizing agent?

Cr2O72-(aq) + 14 H+(aq) + 6 e– → 2 Cr3+(aq) + 7 H2O(l) E° = + 1.33 V

CrO42-(aq) + 4 H2O(l) + 6 e– → Cr(OH)3(s) + 5 OH–(aq) E° = – 0.13 V

A) Cr2O72-

B) Cr3+

C) CrO42-

D) Cr(OH)3

28) What statement is inconsistent with the chemistry of iron?

A) Iron is the fourth most abundant element in the earth’s crust.

B) Iron is obtained from the reduction of hematite (Fe2O3) and magnetite (Fe3O4) by carbon in a blast

furnace.

C) Iron is a relatively hard metal and it is relatively unreactive with haloacids.

D) The majority of iron in a healthy human is present in the oxygen-carrying protein hemoglobin.

29) What are two of the major components of stainless steel?

A) iron and carbon

B) iron and chromium

C) iron and titanium

D) iron and tungsten

30) What statement is most inconsistent about the chemistry of iron?

A) Iron(III) hydroxide is very soluble and reacts readily with hydroxide to form Fe(OH)4–.

B) Iron reacts with hydrochloric acid in the absence of air to yield iron(II) ion and hydrogen gas.

C) Iron reacts with nitric acid to yield iron(III) ion and nitric oxide.

D) The most common oxidation states of iron are +2 (ferrous) and +3 (ferric).

31) What is the strongest oxidizing agent of the following set: FeO, Fe2O3, Fe3O4, FeO42-?

A) FeO

B) Fe2O3

C) Fe3O4

D) FeO42-

32) What statement is inconsistent with the chemistry of copper?

A) It has a high electrical conductivity and is widely used to make electrical wiring.

B) It is commonly found in the elemental state.

C) It is a reddish colored metal that accounts for only 0.0068% of the earth’s crust by mass.

D) It is used to make corrosion-resistant water pipes because it has a positive oxidation potential.

33) Which of the following is a disproportionation reaction?

A) Cu2S(l) + O2(g) → 2 Cu(l) + SO2(g)

B) 3 Cu(s) + 2 NO3-(aq) + 8 H+(aq) → 3 Cu2+(aq) + 2 NO(g) + 4 H2O(l)

C) 2 Cu+(aq) → Cu(s) + Cu2+(aq)

D) Cu2+(aq) + 4 NH3(aq) → Cu(NH3)42+(aq)

34) Using the following reduction potentials for copper determine the unstable copper compound.

Cu+(aq) + e– → Cu(s) E° = +0.52 V

Cu2+(aq) + e– → Cu+(aq) E° = +0.15 V

A) CuCl

B) CuCl2

C) CuSO4

D) Cu(OH)2

35) Describe what happens when 3.0 M NH3 is slowly added to an aqueous solution of CuSO4.

A) A blue precipitate of Cu(OH)2 forms.

B) A royal blue complex of [Cu(NH3)4]2+ is formed.

C) A blue precipitate of Cu(OH)2 is formed which is then converted to the royal blue complex

[Cu(NH3)4]2+.

D) A royal blue complex of [Cu(NH3)4]2+ is formed which then is converted to a blue precipitate of

Cu(OH)2.

36) Which of the following is a stronger acid?

A) Cr3+

B) Cr(OH)2

C) Cr(OH)3

D) CrO2(OH)2

37) What is the coordination number of the Fe atom in K3[Fe(C2O4)3]?

A) 2

B) 3

C) 4

D) 6

38) What is the coordination number of the Au atom in K [Au(CN)2(SCN)2]?

A) 2

B) 3

C) 4

D) 6

39) What is the oxidation state of the Cr atom in [Ni(en)3]3[Cr(CN)6]2?

A) +2

B) +3

C) +4

D) +6

12

40) What is the oxidation state of the Co atom in [Co(NH3)5Cl](NO3)2?

A) +2

B) +3

C) +4

D) +6

41) A chromium(III) ion forms a complex ion with two ammonia molecules and four thiocyanate ions.

What is the formula of the complex ion?

A) [Cr(NH3)2(NCS)4]3+

B) [Cr(NH4)2(NCS)4]+

C) [Cr(NH3)2(NCS)4]–

D) [Cr(NH3)2(NCS)4]4-

42) Which of the following can function as a chelating agent?

A) CN–

B) CO

C) H2NCH2CH2NH2

D) NCS–

43) When the oxalate ion, C2O42- is bonded to the iron(III) ion in the complex ion [Fe(C2O4)3]3-, a

________-membered chelate ring is formed.

A) 3

B) 4

C) 5

D) 6

44) Write the chemical formula for aquabromobis(ethylenediamine)chromium(III) chloride.

13

A) [CrBr(H2O)(en)]Cl

B) [CrBr2(H2O)(en)]Cl2

C) [CrBr(H2O)(en)2]Cl2

D) [CrBr(H2O)(en)2]Cl3

45) Write the chemical formula for pentaamminenitritocobalt(III) ion.

A) [Co(NO)(NH3)5]3+

B) [Co(NO2)(NH3)5]2+

C) [Co(ONO)(NH3)5]2+

D) [Co(NH3)5(N2O)]2+

46) What is the correct formula for tetraamminecarbonatoiron(III) chloride?

A) (NH3)4[FeCO3]Cl

B) [Fe(CO3)(NH3)4]Cl

C) [Fe(CO3)(NH3)4]Cl2

D) [Fe(CO3)Cl(NH3)4]

47) The complex cis–[CoCl(NH3)(NH2CH2CH2NH2)2]2+ was resolved into optical isomers in 1911 by

Alfred Werner, demonstrating the octahedral geometry of the ion. Name this complex ion.

A) cis-chloroammineethylenediaminecobalt(II) ion

B) cis-amminechloroethylenediaminecobalt(III) ion

C) cis-amminechlorobis(ethylenediamine)cobalt(II) ion

D) cis-amminechlorobis(ethylenediamine)cobalt(III) ion

48) What is the name of the complex [Ni(en)3]3[Cr(CN)6]2?

A) ethylenediaminenickel(III) hexacyanochromate(II)

B) tris(ethylenediamine)nickel(III) hexacyanochromate(II)

C) tris(ethylenediamine)nickel(II) hexacyanochromate(III)

D) bis(ethylenediamine)nickel(II) hexacyanochromate(III)

49) What is the name of the complex [Ni(H2O)4(NH2CH2CH2NH2)]SO4 ∙ 5H2O?

A) aquaethylenediaminenickel(II) sulfate hydrate

B) tetraaquaethylenediaminenickel(II) sulfate pentahydrate

C) tetraaquabis(ethylenediamine)nickel(II) sulfate pentahydrate

D) tetraaquabis(ethylenediamine)nickel(III) sulfate pentahydrate

50) What is the name of the complex ion [AuBrCl(CN)2]–?

A) bromochlorodicyanogold(I) ion

B) bromochlorodicyanoaurate(III) ion

C) bromochlorodicyanoargentate(III) ion

D) bromochlorodicyanoaurate(IV) ion

51) Which pair of isomers illustrates the concept of ionization isomers?

A) [Cr(SCN)(NH3)5]2+ and [Cr(NCS)(NH3)5]2+

B) [CoCl(NH3)5]SO4 and [Co(SO4)(NH3)5]Cl

C) cis -[PtCl2(NH3)2] and trans -[PtCl2(NH3)2]

D) (+)-[Co(en)3]3+ and (-)-[Co(en)3]3+

52) The compounds [Cr(H2O)6]Cl3 and [CrCl3(H2O)3] ∙ 3H2O are examples of

A) diastereoisomers.

B) enantiomers.

C) ionization isomers.

D) linkage isomers.

53) Which complex is optically active?

A) [CoCl4en]2-

B) trans-[CrCl2(en)2]+

C) cis-[CrCl2(en)2]+

D) [PtCl2(NH3)2]

54) What hybridization scheme is used for Ni in the square planar complex of [Ni(CN)4]2-?

A) sp3

B) dsp2

C) dsp3

D) d2sp3

55) What type of hybrid orbitals are used by the Ti atom to form chemical bonds in the complex ion

[Ti(H2O)6]3+?

A) sp3

B) dsp2

C) dsp3

D) d2sp3

56) How many unpaired electrons are present in the high spin form of the [CoF6]3- complex and what

metal orbitals are used in bonding?

A) 0 unpaired electrons and 4s, 4p and 4d orbitals to give sp3d2

B) 4 unpaired electrons and 4s, 4p and 4d orbitals to give sp3d2

C) 0 unpaired electrons and 3d, 4s, and 4p orbitals to give d2sp3

D) 4 unpaired electrons and 3d, 4s, and 4p orbitals to give d2sp3

57) Which metal ion is most likely to form a square planar complex ion with CN–?

A) Co2+

B) Cu2+

C) Ni2+

D) Zn2+

58) The complex [Ni(CN)4]2- is diamagnetic and the complex [NiCl4]2- is paramagnetic. What can you

conclude about their molecular geometries?

A) Both complexes have square planar geometries.

B) Both complexes have tetrahedral geometries.

C) [NiCl4]2- has a square planar geometry while [Ni(CN)4]2- has a tetrahedral geometry.

D) [NiCl4]2- has a tetrahedral geometry while [Ni(CN)4]2- has a square planar geometry.

59) Which of the following species is diamagnetic?

A) an isolated, gas-phase V3+ ion

B) a high-spin octahedral Fe2+ complex

C) an isolated, gas-phase Cu2+ ion

D) a low-spin octahedral Co3+ complex

60) What is a representative orbital-filling diagram for the cobalt ion in the low spin complex of

[Co(CN)6]3-?

A) (A)

B) (B)

C) (C)

D) (D)

61) Which of the following complex ions is colorless?

A) [Co(H2O)6]2+

B) [Mn(CN)6]3-

C) [CrCl3(H2O)3]

D) [Ag(NH3)2]+

62) Which of the following complexes are diamagnetic?

[Mn(CN)6]3- [Zn(NH3)4]2+ [Fe(CN)6]4- [FeF6]3-

A) [Zn(NH3)4]2+

B) [Zn(NH3)4]2+ and [FeF6]3-

C) [Zn(NH3)4]2+ and [Fe(CN)6]4-

D) [Mn(CN)6]3–, [Zn(NH3)4]2+ and [Fe(CN)6]4-

63) For an octahedral complex what metal d orbitals are directly towards the ligands?

A) dxy, dxz

B) dxy, dxz, dyz

C) dz², dx²–y²

D) dz², dxz, dyz

64) What is the expected order for increasing octahedral (Δ0) crystal field splitting for the ligands I–, F–,

H2O, NH3, en, CO?

A) I– < F– < H2O < NH3 < en < CO

B) F– < I– < NH3 < en < CO < H2O

C) I– < F– < H2O < CO < NH3 < en

D) CO < en < NH3 < H2O < F– < I–

20

65) What is the expected order for increasing octahedral (Δ0) crystal field splitting for ligands?

A) halides < O ligands < N ligands < CN–

B) halides < CN– < O ligands < N ligands

C) CN– < N ligands < O ligands < halides

D) O ligands < N ligands < CN– < halides

66) What is the crystal field energy level diagram for the complex [Fe(H2O)6]3+?

A) (A)

B) (B)

C) (C)

D) (D)