Deck 23: The Transition Elements and Their Coordination Compounds

Question 1

What is the highest possible oxidation state for molybdenum, Mo?

A) +2
B) +4
C) +6
D) +8
E) none of the above

Answer 1

+6

Question 2

Which of the following atoms has the biggest radius?

A) Ti
B) Cr
C) Fe
D) Ni
E) Zn

Answer 2

Ti

Question 3

A certain transition element has the stable oxidation states of +2, +3, +4, +5, and +6. In which state will the element be most likely to form an ionic bond with chlorine?

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

Answer 3

+2

Question 4

The most common oxidation state for ions of the inner transition elements is

A) +2.
B) +3.
C) +4.
D) +5.
E) +7.

Question 5

What is the highest possible oxidation state for palladium, Pd?

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

Question 6

Which of the following ions is least likely to form colored compounds?

A) Mn²⁺
B) Cr⁵⁺
C) Sc³⁺
D) Fe³⁺
E) Co²⁺

Question 7

The most common oxidation state for ions of the transition elements is

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

Question 8

Which of the following elements has the ground state electron configuration, [Xe]4f¹⁴5d¹⁰6s¹?

A) Hg
B) Ag
C) Hf
D) Au
E) Th

Question 9

Which of the following ions is most likely to form colored compounds?

A) Sc³⁺
B) Cu⁺
C) Zn²⁺
D) Cr³⁺
E) Ca²⁺

Question 10

A certain transition element has the stable oxidation states of +2, +3, +4, +5, and +6. In which state will the element be most likely to form a covalent bond with chlorine?

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

Question 11

Which of the following transition elements can have an oxidation number of +7?

A) V
B) Cr
C) Mn
D) Fe
E) Co

Question 12

How many unpaired electrons are there in the Fe³⁺ ion?

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

Question 13

A feature of transition metal chemistry is that these elements exhibit multiple oxidation states. Which one of the following elements exhibits the smallest number of different oxidation states?

A) Ti
B) Cr
C) Mn
D) Co
E) Zn

Question 14

Which of the following will be paramagnetic?

A) V⁵⁺
B) Ni²⁺
C) Mn⁷⁺
D) Ti⁴⁺
E) Zn

Question 15

Which of the following transition elements can achieve the largest oxidation number?

A) chromium, Cr, Group 6B(6)
B) manganese, Mn, Group 7B(7)
C) iron, Fe, Group 8B(8)
D) cobalt, Co, Group 8B(9)
E) zinc, Zn, Group 2B(12)

Question 16

The ground state electronic configuration of Cr²⁺ is

A) [Ar]4s¹3d⁵.
B) [Ar]4s²3d⁴.
C) [Ar]3d⁴.
D) [Ar]4s¹3d³.
E) [Ar]4s²3d².

Question 17

The ground state electronic configuration of Zn²⁺ is

A) [Ar]4s²3d⁸.
B) [Ar]4s²3d¹⁰.
C) [Ar]4s¹3d⁹.
D) [Ar]3d¹⁰.
E) [Ar]3d⁸.

Question 18

Which of the following will be diamagnetic?

A) Ni²⁺
B) Cr²⁺
C) Mn²⁺
D) Co³⁺
E) Ti⁴⁺

Question 19

If M represents a transition element, which of the following oxides should be the least basic?

A) MO
B) M₂O
C) M₂O₃
D) MO₂
E) MO₃

Question 20

Which one of the following has the ground state electron configuration [Ar]3d¹⁰4s¹?

A) In⁺
B) Cd²⁺
C) Ag⁺
D) Ag
E) Cu

Question 21

Chromium and manganese are among the transition elements that form several different oxides. Which of the following statements characterize these oxides?

A) As the oxidation number on the metal increases, the valence-state electronegativity increases and the oxides change from acidic to basic.
B) As the oxidation number on the metal increases, the valence-state electronegativity increases and the oxides change from basic to acidic.
C) As the oxidation number on the metal increases, the valence-state electronegativity decreases and the oxides change from acidic to basic.
D) As the oxidation number on the metal increases, the valence-state electronegativity decreases and the oxides change from basic to acidic.
E) None of the above statements is correct.

Question 22

What is the coordination number of cobalt in the complex ion [Co(en)Cl₄]^-? (en = ethylenediamine)

A) 1
B) 2
C) 4
D) 6
E) 8

Question 23

The compound K₃[Fe(CN)₆] is used in calico printing and wool dyeing. Give its systematic name.

A) potassium iron(III) hexacyanate
B) tripotassium iron(III) hexacyanate
C) potassium hexacyanoferrate(III)
D) potassium hexacyanideferrate
E) none of the above

Question 24

Which of the following should be the strongest reducing agent?

A) Fe
B) Ru
C) Os
D) Re
E) Cu

Question 25

Aluminum reacts with oxygen in the air to form a protective oxide coating. Silver also reacts with compounds in air to form a black coating. What substance is formed?

A) silver oxide
B) silver chloride
C) silver sulfide
D) silver carbonate
E) silver nitride

Question 26

Give the systematic name for [Cu(NH₃)₄]Cl₂.

A) dichlorotetraamminecuprate(II)
B) tetraamminecopper(II) chloride
C) copper(II) ammonium chloride
D) tetraaminocopper(II) chloride
E) none of the above

Question 27

When the ethylenediaminetetraacetate ion (EDTA^4-) forms a complex with a transition metal ion, how many electrons does it normally donate to the metal?

A) 4
B) 6
C) 8
D) 10
E) 12

Question 28

A certain transition metal complex has the formula MX₄²⁺. If the metal ion has a d⁸ electron configuration, what is the shape of the complex?

A) octahedral
B) square pyramid
C) tetrahedral
D) trigonal pyramid
E) square planar

Question 29

Which of the oxidation states of chromium has the largest valence-state electronegativity?

A) chromium(0)
B) chromium(II)
C) chromium(III)
D) chromium(IV)
E) chromium(VI)

Question 30

The oxidation and coordination numbers of cobalt in the compound [Co(NH₃)₅Cl]Cl₂ are, respectively:

A) 2 and 6.
B) 2 and 8.
C) 3 and 6.
D) 3 and 8.
E) none of the above

Question 31

A characteristic of ligands is that

A) they are Lewis acids.
B) they are Lewis bases.
C) they are ions.
D) they are electron pair acceptors.
E) they are Brønsted-Lowry acids.

Question 32

In the formation of a transition metal complex, the central metal atom or ion acts as

A) an Arrhenius acid.
B) a Bronsted-Lowry acid.
C) a Bronsted-Lowry base.
D) a Lewis acid.
E) a Lewis base.

Question 33

In the compound K[Co(C₂O₄)₂(H₂O)₂] (where C₂O₄^2- = oxalate) the oxidation number and coordination number of cobalt are, respectively:

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

Question 34

Mercury(II) compounds are assimilated into the food chain because

A) they are ionic substances that are concentrated in cell tissue.
B) they complex with compounds in the blood which carries them to the muscle tissue of organisms.
C) they are incorporated into bone structure.
D) they are very soluble in water and easily ingested.
E) they are nonpolar substances that are concentrated in fatty tissues as they move up the food chain.

Question 35

Which of the following will be the strongest oxidizing agent?

A) Cr
B) Cr(II)
C) Cr(III)
D) Cr(IV)
E) Cr(VI)

Question 36

In the compound [Ni(en)₂(H₂O)₂]SO₄ (where en = ethylenediamine) the oxidation number and coordination number of nickel are, respectively:

A) 2 and 6.
B) 4 and 6.
C) 6 and 6.
D) 2 and 4.
E) 4 and 4.

Question 37

Which of the following coordination numbers applies to octahedral complexes?

A) 4
B) 5
C) 6
D) 8
E) none of the above

Question 38

Which of the following is not a property of silver that is important in black and white photography?

A) Silver halides are not soluble in water.
B) Silver metal is easily oxidized.
C) Silver halides undergo a redox reaction when exposed to light.
D) Silver ions will form stable, water-soluble complex ions.
E) Silver atoms catalyze the reduction of silver ions.

Question 39

Which one of the following normally acts as a bidentate ligand in complexes with transition metal ions?

A) CN^-
B) EDTA^4-
C) SCN^-
D) ethylene diamine
E) ethylene, C₂H₄

Question 40

Which of the following is considered a bidentate ligand?

A) cyanide, CN^-
B) thiocyanate, SCN^-
C) oxalate, C₂O₄^2-
D) nitrite, NO₂^-
E) hydroxide, OH^-

Question 41

Consider the following structures (1 and 2 are octahedral; 3 and 4 are square planar). Which one of the following statements about the above structures is correct?

A) 1 and 2 are superimposable.
B) 1 and 2 are geometric isomers.
C) 3 and 4 are structural isomers.
D) 3 and 4 are optical isomers.
E) 3 and 4 are geometric isomers.

Question 42

According to Valence Bond theory, in the square planar Ni(CN)₄^2- complex ion, the orbital hybridization pattern is

A) sp³.
B) dsp².
C) d²sp.
D) d²sp³.
E) none of the above.

Question 43

Write the formula for pentaamminechlorocobalt(III) chloride.

A) [Co(NH₃)₅Cl]Cl
B) [Co(NH₃)₅Cl]Cl₂
C) [Co(NH₃)₅Cl]Cl₃
D) [Co(NH₃)₅Cl]Cl₄
E) none of the above

Question 44

In a coordination compound involving a complex ion of square planar geometry, which of the following types of isomerism is/are never possible?

A) geometric
B) optical
C) linkage
D) coordination
E) more than one of the above

Question 45

Give the systematic name for Cr(CO)₃(NH₃)₃.

A) chromiumtriaminotricarbonyl
B) triamminechromium carbonate
C) triamminetricarbonylchromate(0)
D) triamminetricarbonylchromium(0)
E) none of the above

Question 46

The crystal field splitting energy, $\Delta$ ,

A) is larger for tetrahedral complexes than for octahedral complexes.
B) depends on the metal but not on the ligand.
C) determines the color of a complex.
D) is larger for ionic ligands like chloride than for molecular ligands like carbon monoxide, CO.
E) determines the charge of a complex.

Question 47

According to valence bond theory, what would be the set of hybrid orbitals used when a Period 4 transition metal forms a tetrahedral complex?

A) d²sp
B) dsp²
C) dsp³
D) sp³
E) d²p²

Question 48

Which of the following species could exist as isomers?

A) [Co(H₂O)₄Cl₂]⁺
B) [Pt(NH₃)Br₃]^-
C) [Pt(en)Cl₂]
D) [Pt(NH₃)₃Cl]⁺
E) none of the above

Question 49

Which of the following ions could exist in only the high-spin state in an octahedral complex?

A) Cr²⁺
B) Mn⁴⁺
C) Fe³⁺
D) Co³⁺
E) Ni²⁺

Question 50

Which of the following ions could exist in either the high-spin or low-spin state in an octahedral complex?

A) Sc³⁺
B) Ni²⁺
C) Mn²⁺
D) Ti⁴⁺
E) Zn²⁺

Question 51

Consider the following octahedral complex structures, each involving ethylene diamine and two different, unidentate ligands X and Y. Which one, if any, of the following is a pair of optical isomers?

A) 1 and 2
B) 1 and 3
C) 1 and 4
D) 3 and 4
E) none of the above

Question 52

Write the formula for sodium tetracyanonickelate(II).

A) Na[Ni(CN)₄]
B) Na[Ni(CN)₄]₂
C) Na₂[Ni(CN)₄]
D) Na₄[Ni(CN)₄]
E) none of the above

Question 53

Consider the following octahedral complex structures, each involving ethylene diamine and two different, unidentate ligands X and Y. Which one of the following statements about these structures is incorrect?

A) Structures 1 and 2 are optical isomers.
B) Structures 1 and 3 are optical isomers.
C) Structures 1 and 3 are different complexes.
D) Structures 1 and 4 are geometrical isomers.
E) Structures 3 and 4 are the same complex.

Question 54

Write the formula for diamminedichloroethylenediaminecobalt(III) bromide.

A) [CoCl₂(en)(NH₃)₂]Br
B) [CoCl₂(en)(NH₃) ₂]Br₂
C) [CoCl₂(en)₂(NH₃)₂]Br
D) [CoCl₂(en)₂(NH₃) ₂]Br₂
E) none of the above

Question 55

According to valence bond theory, what would be the set of hybrid orbitals used when a Period 4 transition metal forms a square planar complex?

A) d²sp
B) d²p²
C) dsp³
D) sp³
E) dsp²

Question 56

In the presence of a strong octahedral ligand field, the number of unpaired electrons in Co(III) will be

A) 0.
B) 2.
C) 4.
D) 6.
E) none of the above.

Question 57

Which of the following octahedral complexes should have the largest crystal field splitting energy, $\Delta$ ?

A) [Cr(H₂O)₆]³⁺
B) [Cr(SCN)₆]^3-
C) [Cr(NH₃)₆]³⁺
D) [Cr(CN)₆]^3-
E) [Cr(en)₃]³⁺ (en = ethylenediamine)

Question 58

Give the systematic name for [CoCl₃(H₂O)]^-.

A) cobalt(II) chloride monohydrate
B) aquatrichlorocobalt(II)
C) aquatrichlorocobaltate(II)
D) aquatrichlorocobaltite(I)
E) none of the above

Question 59

In the spectrochemical series, which one of the following ligands has the strongest field?

A) H₂O
B) CN^-
C) NH₃
D) OH^-
E) Cl^-

Question 60

Which of the following ligands could participate in linkage isomerism?

A) NH₃
B) H₂O
C) NH₄⁺
D) NO₂^-
E) ethylenediamine

Question 61

The M²⁺ ions of the first transition series of elements all have the general electronic configuration [Ar]4s²3d^x, where x is an integer from 1 to 8.

Question 62

Give one important use of the following metals or their compounds.
a. chromium
b. manganese
c. mercury
d. silver

Question 63

Which of the following ligands is most likely to form a high spin octahedral complex with cobalt(II)?

A) CN^-
B) en (ethylenediamine)
C) NO₂^-
D) CO
E) I^-

Question 64

What geometry is particularly common for complexes of d¹⁰ metal ions?

Question 65

a. How can the formation of a complex ion be described in terms of a theory of acids and bases?
b. What is the essential requirement for a molecule or ion to act as a ligand?

Question 66

Which of the following ligands is most likely to form a low-spin octahedral complex with iron(III)?

A) Cl^-
B) H₂O
C) NH₃
D) OH^-
E) CO

Question 67

All atoms of the first transition series of elements have the ground state electronic configuration [Ar]4s²3d^x, where x is an integer from 1 to 10.

Question 68

Apply the valence bond theory to predict the electronic structure and hybridization pattern of chromium in the complex ion Cr(NH₃)₆³⁺.

Question 69

The Cu²⁺ ion has 1 unpaired electron.

Question 70

The d_xy and the d_x²_-y² orbitals both lie in the xy plane, yet for a metal ion in an octahedral complex the energy of the d_xy orbital is lower than that of the d_x²_-y²orbital. Explain this using the arguments of crystal field theory.

Question 71

The ground state electron configuration of a transition element atom cannot have more than one incomplete subshell.

Question 72

How many unpaired electrons will there be in a high-spin octahedral complex of Fe(II)?

A) 0
B) 2
C) 4
D) 6
E) none of the above

Question 73

What is the difference between a coordination compound and a complex ion?

Question 74

Iron(III) forms an octahedral complex with the ligand CN^-. How many unpaired electrons are in the d orbitals of iron?

A) 1
B) 3
C) 5
D) 7
E) none of the above

Question 75

a. Explain how the crystal field theory can use the magnitude of the splitting energy $\Delta$ to provide an explanation of the color and magnetic properties of octahedral complexes.
b. In promoting an electron from the t_2g set of orbitals to the e_g set, an octahedral complex absorbs a photon with a wavelength $\lambda$ of 523 nm. Calculate the value of $\Delta$ in the complex, in kJ/mol.

Question 76

The compound Rh(CO)(H)(PH₃)₂ forms cis and trans isomers. Use this information to predict the geometry of this complex, and draw the geometric isomers.

Question 77

If a solution absorbs green light, what is its likely color?

A) red
B) violet
C) orange
D) yellow
E) blue

Question 78

Why is the +2 oxidation state so common among transition elements?

Question 79

a. State the requirement for two molecules to be optical isomers.
b. A complex ion MABCD²⁺ (where A, B, C, and D are different unidentate ligands) rotates the plane of polarized light. Deduce the geometry of the complex and draw the optical isomers of this ionic formula.

Question 80

a. How many unpaired 3d electrons will there be in (i) high and (ii) low-spin complexes of Co(II)?
b. How can high and low-spin complexes be recognized and distinguished experimentally?