Deck 20: The Chemistry of Coordination Compounds

Question 1

The total number of electrons in the 3d orbitals of Ti³⁺ is

A)0.
B)1.
C)2.
D)3.
E)4.

Answer 1

1.

Question 2

How many 3d electrons does a Mn²⁺ ion have?

A)1
B)2
C)3
D)4
E)5

Answer 2

5

Question 3

The electron configuration of a nickel atom is

A)[Ar]4s²3d⁶.
B)[Ar]4s¹3d⁷.
C)[Ar]3d⁸.
D)[Ar]4s²3d⁸.
E)[Ar]3d¹⁰.

Answer 3

[Ar]4s²3d⁸.

Question 4

In the complex ion [Cr(C₂O₄)₂(H₂O)₂]^-, the oxidation number of Cr is

A)+1.
B)+2.
C)+3.
D)-2.
E)-1.

Question 5

The electron configuration of a Cr³⁺ ion is

A)[Ar]3d⁵.
B)[Ar]4s¹3d².
C)[Ar]3d³.
D)[Ar]4s¹3d⁵.
E)[Ar]4s²3d⁴.

Question 6

The total number of electrons in the 3d orbitals of a copper atom is

A)6.
B)7.
C)8.
D)9.
E)10.

Question 7

In K₄[Fe(CN)₆], how many 3d electrons does the iron atom have?

A)3
B)4
C)5
D)6
E)7

Question 8

How many 3d electrons does a V³⁺ ion have?

A)6
B)5
C)4
D)3
E)2

Question 9

Assuming a coordination complex is formed with Fe²⁺ and 1,10-phenanthroline (shown below), which of the following statements is true?

A)If two 1,10-phenanthroline molecules are coordinated to the iron ion, then the coordination number is 2.
B)If two 1,10-phenanthroline molecules are coordinated to the iron ion, then the coordination number is 6.
C)If three 1,10-phenanthroline molecules are coordinated to the iron ion, then the coordination number is 3.
D)If three 1,10-phenanthroline molecules are coordinated to the iron ion, then the coordination number is 6.
E)If four 1,10-phenanthroline molecules are coordinated to the iron ion, then the coordination number is 4.

Question 10

The electron configuration of a Co³⁺ ion is

A)[Ar]3d⁶.
B)[Ar]4s¹3d⁵.
C)[Ar] 4s²3d⁴.
D)[Ar]3d⁵.
E)[Ar]3d⁴.

Question 11

In the complex ion [Fe(CN)₆]^4-, the oxidation number of Fe is

A)+1.
B)+2.
C)+3.
D)-4.
E)+6.

Question 12

Which response gives the correct coordination number (C.N.)and oxidation number (O.N.)of the transition metal atom in [Co(NH₃)₂(H₂O)₂Cl₂]⁺?

A)C.N. = 2; O.N. = +3
B)C.N. = 3; O.N. = +1
C)C.N. = 4; O.N. = +2
D)C.N. = 6; O.N. = +1
E)C.N. = 6; O.N. = +3

Question 13

The electron configuration of a Ti atom is

A)[Ne]3s²3d².
B)[Ne] 3s²4d².
C)[Ar]4s²3d².
D)[Ar]4s²4d².
E)[Ar]3d⁴.

Question 14

The total number of electrons in the 3d orbitals of a titanium atom is

A)1.
B)2.
C)3.
D)4.
E)5.

Question 15

In the complex ion [Co(en)₂Br₂]⁺, the oxidation number of Co is

A)+1.
B)+2.
C)+3.
D)-2.
E)-1.

Question 16

The electron configuration of an Fe²⁺ ion is

A)[Ar]4s²4d⁴.
B)[Ar]4s²3d⁶.
C)[Ar]3d³.
D)[Ar]3d⁵.
E)[Ar]3d⁶.

Question 17

How would you expect the molecule 1,10-phenanthroline (shown below)to function as a ligand?

A)It would be expected to be a monodentate ligand.
B)It would be expected to be a bidentate ligand.
C)It would be expected to be a tridentate ligand.
D)It would be expected to be a tetradentate ligand.
E)It would not be expected to function as a ligand.

Question 18

The total number of electrons in the 3d orbitals of Cr³⁺ is

A)1.
B)2.
C)3.
D)4.
E)5.

Question 19

Give the coordination number (C.N.)and oxidation number (O.N.)of the metal atom in the coordination compound [Cr(NH₃)₂(en)Cl₂].

A)C.N. = 4; O.N. = +2.
B)C.N. = 5; O.N. = +3.
C)C.N. = 5; O.N. = +2.
D)C.N. = 6; O.N. = +3.
E)C.N. = 6; O.N. = +2.

Question 20

The total number of electrons in the 3d orbitals of Co³⁺ is

A)4.
B)5.
C)6.
D)7.
E)10.

Question 21

Which of these complex ions would absorb light with the longest wavelength?

A)[Co(H₂O)₆]²⁺
B)[Co(NH₃)₆]²⁺
C)[CoF₆]^4-
D)[Co(CN)₆]^4-
E)[Co(en)₆]²⁺

Question 22

The correct formula for the dichlorobis(ethylenediamine)chromium(III)ion is

A)[Cr(en)₂Cl₂]³⁺.
B)[Cr(en)Cl₂]⁺.
C)[Cr(en)₂Cl₂]²⁺.
D)[Cr(en)₂Cl₂]⁺.
E)[Cr(en)₃Cl₂]⁺.

Question 23

The best name for K₄[FeCl₂(CN)₄] is

A)tetrapotassium dichlorodicyanoiron(II).
B)potassium dichlorodicyanoiron(II).
C)potassium dichlorodicyanoferrate(III).
D)tetrapotassium dichlorobis(cyano)iron(III).
E)potassium dichlorotetracyanoferrate(II).

Question 24

In the coordination compound [Cr(NH₃)(en)₂Cl]Br₂, the coordination number (C.N.)and oxidation number (O.N.)of the metal atom are, respectively,

A)C.N. = 6; O.N. = +4.
B)C.N. = 6; O.N. = +3.
C)C.N. = 5; O.N. = +2.
D)C.N. = 4; O.N. = +2.
E)C.N. = 4; O.N. = +3.

Question 25

In the coordination compound [Co(en)₂Cl₂]Cl, the coordination number and oxidation number of the central atom are, respectively,

A)4, +3.
B)6, +2.
C)4, +2.
D)6, +3.
E)4, +1.

Question 26

In the coordination compound [Pt(NH₃)₂Cl₂], the coordination number and oxidation number of the central atom are, respectively,

A)2, 0.
B)4, 4.
C)5, 0.
D)4, 2.
E)6, 2.

Question 27

The best name for the complex shown below is

A)cobalt(III)bis(ethylenediamine)bromide.
B)dibromobis(ethylenediamine)cobalt(III)bromide.
C)dibromidedi(ethylenediamine)cobalt(III)bromide.
D)dibromodiethylenediaaminecobalt(III)bromide.
E)tribromobis(ethylenediamine)cobalt(III).

Question 28

Which of these ligands produces the strongest crystal field?

A)Cl^-
B)CO
C)OH^-
D)H₂O
E)NH₃

Question 29

The coordination compound shown below has

A)two monodentate ligands and two bidentate ligands.
B)three monodentate ligands and two bidentate ligands.
C)four monodentate ligands and two bidentate ligands.
D)one monodentate ligand and four bidentate ligands.
E)four bidentate ligands.

Question 30

Which of these electron energy level patterns would absorb light with the shortest wavelength?

A)A
B)B
C)C
D)D

Question 31

The numbers of geometrical isomers and optical isomers of the complex ion [Co(en)₃]³⁺ are, respectively,

A)2 and 2.
B)1 and 1.
C)3 and 2.
D)1 and 2.
E)2 and 4.

Question 32

Which of these ligands produces the weakest crystal field?

A)CN^-
B)I^-
C)OH^-
D)H₂O
E)NH₃

Question 33

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has five d electrons and L is a strong field ligand. According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

A)0
B)1
C)2
D)3
E)5

Question 34

Which of these square planar complex ions can have cis-trans isomers?

A)[Pt(NH₃)₄]²⁺
B)[Ni(NH₃)₄]²⁺
C)[Pt(NH₃)₂Cl₂]
D)[Pt(NH₃)Cl₃]^-
E)[Ni(NH₃)₃Cl]⁺

Question 35

A complex with the composition [MA₂B₂]X₂ is found to have no geometrical isomers. Both A and B are monodentate ligands. The structure of the complex is

A)linear.
B)square planar.
C)tetrahedral.
D)octahedral.

Question 36

In the coordination compound K₂[Co(en)Cl₄], the coordination number (C.N.)and oxidation number (O.N.)of cobalt are

A)C.N. = 6; O.N. = +2.
B)C.N. = 6; O.N. = +3.
C)C.N. = 5; O.N. = +2.
D)C.N. = 5; O.N. = +4.
E)C.N. = 4; O.N. = +3.

Question 37

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has seven d electrons and L is a weak field ligand. According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

A)0
B)1
C)2
D)3
E)5

Question 38

Cis-trans isomerism is exhibited by which one of these ions?

A)[Pd(NH₃)₃Cl]⁺
B)[Co(NH₃)₅Cl]²⁺
C)[Fe(CN)₆]^3-
D)All of the above.
E)None of the above.

Question 39

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has six d electrons and L is a weak field ligand. According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

A)0
B)1
C)2
D)3
E)4

Question 40

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has seven d electrons and L is a strong field ligand. According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

A)0
B)1
C)2
D)3
E)5

Question 41

Labile complexes are coordination complexes that

A)are labeled with a radioactive isotope.
B)are thermodynamically stable.
C)are thermodynamically unstable.
D)undergo rapid ligand exchange reactions.
E)undergo very slow ligand exchange reactions.

Question 42

What is the oxidation number of Fe in [Fe(CN)₆]^4- ?

Question 43

The ion [Co(NH₃)₆]²⁺ is octahedral and high spin. This complex is

A)paramagnetic, with 1 unpaired electron.
B)paramagnetic, with 3 unpaired electrons.
C)paramagnetic, with 4 unpaired electrons.
D)paramagnetic, with 5 unpaired electrons.
E)diamagnetic.

Question 44

Two well-known complex ions containing Ni are [Ni(H₂O)₆]²⁺, which is green, and [Ni(en)₃]²⁺, which is purple. Which one of these statements is true?

A)The crystal field splitting energy ( $\Delta$ )is greater for [Ni(en)₃]²⁺ than for [Ni(H₂O)₆]²⁺.
B)[Ni(en)₃]²⁺ absorbs energy in the red region of the spectrum.
C)Both complex ions are diamagnetic.
D)[Ni(H₂O)₆]²⁺ transmits light with wavelengths of approximately 650-700 nm.
E)The green complex absorbs green light.

Question 45

Two complex ions containing Ni are [Ni(NH₃)₆]²⁺, which is blue, and [Ni(en)₃]²⁺, which is purple. Which one of these statements is true?

A)The crystal field splitting energy ( $\Delta$ )is greater for [Ni(NH₃)₆]²⁺ than for [Ni(en)₃]²⁺.
B)[Ni(en)₃]²⁺ absorbs light in the violet region of the spectrum.
C)Both complex ions are diamagnetic.
D)The energy of the photon absorbed by [Ni(en)₃]²⁺ is greater than that absorbed by [Ni(NH₃)₆]²⁺.
E)The wavelength of the light absorbed by [Ni(en)₃]²⁺ is greater than the wavelength absorbed by [Ni(NH₃)₆]²⁺.

Question 46

A molecule or ion that provides an electron pair for coordinate covalent bond formation is called a Lewis ________.

Question 47

How many unpaired electrons does the manganese ion have in [Mn(CN)₆]^4- ?

A)1 unpaired electron
B)2 unpaired electrons
C)3 unpaired electrons
D)5 unpaired electrons
E)No unpaired electrons

Question 48

Write the chemical formula of triammineaquodichlorochromium(III)chloride.

Question 49

Consider the [CoCl₆]^4- ion. Which response includes all the following statements that are true and no false statements? I. The oxidation number of Co is -4.
II. The coordination number of cobalt is 6.
III. It is paramagnetic.
IV. It is a low-spin complex.

A)I, II, III, IV
B)I, IV
C)II, III
D)I, III
E)III, IV

Question 50

How many geometric isomers are possible for the complex [CrF₃Br₃]^3-? Draw these isomers.

Question 51

Write the chemical formula of the dibromobis(oxalato)cobaltate(III)ion.

Question 52

What is the oxidation number of cobalt in [Co(NH₃)₆]Cl₃?

Question 53

Write the chemical formula of diamminedichloroplatinum(II).

Question 54

A molecule or atom that accepts an electron pair to form a coordinate covalent bond is called a Lewis _______.

Question 55

What is the coordination number of silver in [Ag(NH₃)₂]Cl?

Question 56

What terms describe the geometric isomers that are possible for the complex [CrF₂Cl₄]^3-?

Question 57

What is the coordination number of cobalt in [Co(NH₃)₆]Cl₃?

Question 58

Name the complex ion [Ni(CN)₄]^2-.

Question 59

Draw and label the geometric isomers of [CrF₂Cl₄]^3-?

Question 60

How many unpaired electrons are there in the complex ion [Mn(CN)₆]^3- ?

A)0
B)1
C)2
D)3
E)4

Question 61

Name the complex ion [CuCl₃Br(NH₃)₂]^2-.

Question 62

In the following pair of complex ions, choose the one that absorbs light at a shorter wavelength.

A)[Co(NH)₆]³⁺
B)[CoCl₆]^3-

Question 63

Bidentate and polydentate ligands are also called chelating agents.

Question 64

Predict the number of unpaired electrons in the [CrCl₆]^4- ion.

Question 65

Predict the number of unpaired electrons in the [Fe(CN)₆]^3- ion.

Question 66

In the following pair of complex ions, choose the one that absorbs light at a longer wavelength.

A)[Co(H₂O)₆]²⁺
B)[Co(NH₃)₆]²⁺

Question 67

The systematic name of the coordination compound K₂[Co(H₂O)₂I₄] is potassium diaquotetraiodocobaltate(II).

Question 68

The correct formula for the dibromobis(oxalato)cobaltate(III)ion is [Co(C₂O₄)Br₂]³⁺.

Question 69

The neutral monodentate ligand L forms the complex ion [CrL₆]²⁺, and the magnetic properties of this complex correspond to 2 unpaired electrons. Is L a strong-field or weak-field ligand? Explain your reasoning.

Question 70

Name the complex ion [Co(H₂O)₄Cl₂]⁺.

Question 71

Give (a)the oxidation number of the metal, (b)the number of d electrons, (c)the coordination number, (d)the charge of the complex ion, and (e)the number and type of ligands for the coordination compound shown below.

Question 72

Name the complex ion [Cr(en)₂(H₂O)₂]²⁺.

Question 73

Predict the number of unpaired electrons in the [Fe(CN)₆]^4- ion.

Question 74

Predict the number of unpaired electrons in the [Cr(en)₃]²⁺ ion.

Question 75

In transition metal complexes, the metal ions are Lewis acids.

Question 76

The oxidation number of Co in [Co(NH₃)₄Cl₂]Cl is +1.