Deck 17: Metal Ions: Colorful and Essential

Question 1

Which of the following species is a Lewis base?

A) H⁺
B) Cs⁺
C) NF₃
D) NF₄⁺
E) NH₄⁺

Answer 1

NF₃

Question 2

A Lewis base is any species capable of ________ an electron pair.

A) accepting
B) donating
C) creating
D) neutralizing
E) gaining

Answer 2

donating

Question 3

A ligand is any ________ forming a coordinate bond to a metal cation.

A) Lewis acid
B) ion
C) Lewis base
D) organic compound
E) species

Answer 3

Lewis base

Question 4

The bonds between the zinc ion and the nitrogen atoms in the complex Zn(NH₃)₄²⁺ are best described as ________

A) ionic.
B) covalent.
C) coordinate covalent.
D) polar covalent.
E) d-electron bonds.

Question 5

Which statement A-D regarding acids and bases is not correct?

A) A Lewis base is an electron-pair donor; a Lewis acid is an electron-pair acceptor.
B) A Brønsted-Lowry base is a proton acceptor; a Brønsted-Lowry acid is a proton donor.
C) A Lewis base can accept a proton from a Brønsted-Lowry acid.
D) Coordinate covalent bonds in transition metal compounds are formed when a Lewis base reacts with a Lewis acid.
E) Statements A-D are all correct.

Question 6

A Lewis acid is ________

A) a proton donor.
B) a proton acceptor.
C) an electron-pair donor.
D) an electron-pair acceptor.
E) never viewed also as a Brønsted-Lowry acid.

Question 7

The bond between a metal cation and a ligand can best be described as ________

A) an ionic bond.
B) a covalent bond.
C) a coordinate covalent bond.
D) a polar covalent bond.
E) a bidentate bond.

Question 8

Identify the Lewis base in the following reaction:
PH₃(g) + H⁺(g) $\rightarrow$ PH₄⁺(g)

A) PH₃
B) H⁺
C) PH₄⁺
D) None of these is a base.
E) All of these are bases.

Question 9

A Lewis base is ________

A) an electron-pair acceptor.
B) an electron-pair donor.
C) a proton donor.
D) a proton acceptor.
E) never viewed also as a Brønsted-Lowry base.

Question 10

A Lewis acid is any species capable of ________ an electron pair.

A) accepting
B) donating
C) creating
D) neutralizing
E) losing

Question 11

A coordinate covalent bond forms when ________

A) a chemical species donates one electron to another species to form a covalent bond.
B) a chemical species donates a pair of electrons to another species to form a covalent bond.
C) a chemical species accepts one electron from another species to form a covalent bond.
D) a chemical species accepts an electron and becomes an anion.
E) a chemical species accepts a pair of electrons and becomes an anion.

Question 12

In the following reaction, which species is the Lewis acid?
Cu²⁺ + NH₃ $\leftrightarrow$ Cu(NH₃)²⁺

A) Cu²⁺
B) NH₃
C) [Cu(NH₃)]²⁺
D) None of these is an acid.
E) All of these are acids.

Question 13

Identify the Lewis acid in the following reaction:
PH₃(g) + H⁺(g) $\rightarrow$ PH₄⁺(g)

A) PH₃
B) H⁺
C) PH₄⁺
D) None of these is an acid.
E) All of these are acids.

Question 14

When Ni(NH₃)₆Cl₂ dissolves in water, which of the following species form the inner coordination sphere around the Ni²⁺ ions?

A) Other Ni²⁺ ions
B) Cl^- ions
C) H₂O molecules with O closest to the Ni²⁺ ions
D) H₂O molecules with H closest to the Ni²⁺ ions
E) NH₃

Question 15

Which statement A-D regarding transition metal coordination compounds is not correct?

A) A coordination compound is formed when a Lewis acid reacts with a Lewis base.
B) Many, but not all, coordination compounds consist of a complex ion and some number of counter ions.
C) The Lewis bases attached to the metal ion are called ligands.
D) A coordination compound has no net electrical charge.
E) Statements A-D are all correct.

Question 16

Which statement A-D regarding a complex ion in a transition metal coordination compound is not correct?

A) The complex ion consists of a metal cation bonded to ligands through coordinate covalent bonds.
B) The ligands in the complex ion are Lewis bases.
C) The ligands are said to occupy the inner coordination sphere.
D) The coordination number is the number of electron pairs bonded to the metal cation.
E) All complex ions have a net positive charge.

Question 17

A ligand is best described as ________

A) a Lewis acid.
B) a Lewis base.
C) a Brønsted-Lowry acid.
D) a Brønsted-Lowry base.
E) an ion.

Question 18

Which of the following species is least likely to function as a ligand in a transition metal complex ion?

A) NH₄⁺
B) NH₃
C) Cl^-
D) H₂O
E) OH^-

Question 19

When NF₃ reacts with BF₃ to form F₃NBF₃, ________

A) a coordinate covalent bond is formed.
B) an ionic bond is formed.
C) the bond is formed by sharing an electron from NF₃ and an electron from BF₃.
D) a complex ion is formed.
E) a covalent bond is formed.

Question 20

In the following reaction, which species is the Lewis base?
Cu²⁺ + NH₃ $\leftrightarrow$ Cu(NH₃)²⁺

A) Cu²⁺
B) NH₃
C) [Cu(NH₃)]²⁺
D) None of these is a base.
E) All of these are bases.

Question 21

Determine the molar concentration of Ag⁺(aq) ions in a 1.00 M solution of AgCl₂^- with no excess chloride.
Given: K_f = 2.50 * 10⁵ for AgCl₂^-.

A) 2.52 *10^-2 M
B) 1.26 * 10^-2 M
C) 0.0100 M
D) 0.0020 M
E) 2.50 * 10⁵ M

Question 22

The coordination number for copper in the compound K₂[CuCl₄] is ________

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

Question 23

The coordination number around the Co ion in [Co(NH₃)₆][CrF₆] is ________

A) 2.
B) 1.
C) 6.
D) 5.
E) 7.

Question 24

In Na₂[Zn(CN)₄], the counter ion is ________, and in [Co(NH₃)₄Cl₂]NO₃, the counter ion is ________.

A) CN^-; NO₃^-
B) Na⁺; NO₃^-
C) CN^-; Cl^-
D) Na⁺; Cl^-
E) Zn²⁺; Co³⁺

Question 25

Lead poisoning used to be treated by injections of ethylenediaminetetraacetic acid, EDTA. If the concentration of EDTA in the blood of a patient is 3.0*10^-9 M and the formation constant for Pb(EDTA)^2- is 2.0 * 10¹⁸, what is the concentration ratio of free toxic Pb²⁺ to lead-EDTA complex in the blood?

A) 2.0 *10^-11
B) 1.7 *10^-10
C) 2.0 * 10^-9
D) 5.0 * 10^-19
E) 3.0 * 10^-9

Question 26

In K₄[Fe(CN)₆], the counter ion is ________, and in [Co(NH₃)₄Cl₂]NO₃, the counter ion is ________.

A) CN^-; NO₃^-
B) K⁺; NO₃^-
C) CN^-; Cl^-
D) K⁺; Cl^-
E) Fe²⁺; Co³⁺

Question 27

The coordination number for [Pt(NH₃)₄]Cl₂ is ________

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

Question 28

Lead poisoning used to be treated by injections of ethylenediaminetetraacetic acid, EDTA. If the concentration of EDTA in the blood of a patient is 3.0 *10^-7 M and the formation constant for Pb(EDTA)^2- is 2.0 *10¹⁸, what is the concentration ratio of free toxic Pb²⁺ to lead-EDTA complex in the blood?

A) 2.0 *10^-11
B) 1.7 * 10^-12
C) 2.0 *10^-9
D) 5.0 *10^-19
E) 3.0 F* 10^-9

Question 29

For the coordination compound K₃[Fe(CN)₆], identify, in order, the charge on the complex ion, the oxidation state of the metal, and the coordination number of the metal. If none of A-D is correct, respond E.

A) 3+,3-, 6+
B) 0, 0, 6+
C) 3-, 3+, 3+
D) 3-, 3+, 6+
E) None of these choices is correct.

Question 30

How many ions are formed when [Co(NH₃)₅Cl]Cl₂ dissolves in water?

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

Question 31

What is the shape of Zn(OH)₄^2-?

A) triangular pyramid
B) tetrahedral
C) octahedral
D) square pyramid
E) T-shaped

Question 32

The coordination number for Pt(NH₃)₄²⁺ is ________

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

Question 33

What do you predict for the geometry of Ti(H₂O)₆³⁺?

A) octahedral
B) tetrahedral
C) square planar
D) trigonal bipyramidal
E) square pyramidal

Question 34

What is the molar concentration of Ag⁺(aq) in a 1.00 M solution of Ag(NH₃)₂⁺ with no excess ammonia?
Given: K_f = 1.70 * 10⁷ for Ag(NH₃)₂⁺.

A) 2.45 * 10^-3 M
B) 3.09 *10^-3 M
C) 2.42 * 10^-4 M
D) 1.47 * 10^-8 M
E) 1.70 *10^-8 M

Question 35

The complex ion Fe(H₂O)₆³⁺ has 5 unpaired electrons in 3d orbitals. Given this information, which iron orbitals would you expect to be hybridized and used to form the coordinate covalent bonds with water?

A) 4s, 4p, and 4d
B) 3s and 3p
C) 3s, 3p, and 3d
D) 4s, 4p, and 3d
E) 4s and 4p

Question 36

What is the oxidation state of the cobalt atom in the [Co(NH₃)₄Cl₂]⁺ complex ion?

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

Question 37

Which orbital hybridization in a metal atom would be appropriate for octahedral complexes?

A) sp
B) sp²
C) sp²d
D) sp³d
E) sp³d²

Question 38

What is the shape of the complex ion CoF₆^3-?

A) square pyramidal
B) octahedral
C) tetrahedral
D) trigonal bipyramidal
E) square planar

Question 39

What would you predict for the hybridization of the Zn orbitals, based on the tetrahedral geometry of Zn(OH)₄^2-?

A) sp³d²
B) sp³
C) sp²d
D) sp³d
E) p²d²

Question 40

The coordination number around the Cr ion in [Co(NH₃)₆][CrF₆] is ________

A) 2.
B) 1.
C) 6.
D) 5.
E) 7.

Question 41

What is the chemical formula of amminetrichloroplatinate(II)?

A) [Pt₂(NH₃)Cl₃]^-
B) [Pt(NH₃)₃Cl]^-
C) [Pt(NH₃)Cl₃]^2-
D) [Pt(NH₃)Cl₃]⁺
E) [Pt(NH₃)Cl₃]^-

Question 42

The correct name for [Co(NH₃)₅Cl]Cl₂ is ________

A) pentaamminechlorocobalt(III) chloride.
B) pentaamminechlorocobalt(II) chloride.
C) chloropentaamminecobalt(III) chloride.
D) pentaamminechlorocobaltate(III) chloride.
E) pentaamminedichlorocobalt(III).

Question 43

Determine the molar concentration of Cl^- ions in a 1.00 M solution of AgCl₂^- with no excess silver ions.
Given: K_f = 2.5*10⁵ for AgCl₂^-.

A) 0.020 M
B) 0.0040 M
C) 3.2 * 10^-2 M
D) 2.5 * 10^-2 M
E) 2.5 * 10⁵ M

Question 44

What will be the equilibrium concentration of silver(I) ion in an aqueous solution originally containing 0.00100 M Ag⁺ and 0.500 M 1,10-phenanthroline?
Ag⁺(aq) + 2phen $\leftrightarrow$ [Ag(phen)₂]⁺ K_f = 1.2 * 10¹²
[Ag (phen)₂]⁺

A) 9 *10^-7 M
B) 8 *10^-13 M
C) 6 * 10^-6 M
D) 3.4 *10^-15 M
E) 1.2 *10^-12 M

Question 45

The correct name for the compound [Fe(NH₃)₅H₂O](NO₃)₂ is ________

A) pentaammineaquairon(II) nitrate.
B) pentaammineaquairon(III) nitrate.
C) pentaammineaquaferrate(II) nitrate.
D) aquapentaammineiron(II) nitrate.
E) pentaammineaquadinitroiron(III).

Question 46

The correct formula for ammonium tetracyanoplatinate(II) is ________

A) (NH₃)₂[Pt(CN)₄].
B) (NH₄)₂[Pt(CN)₄].
C) (NH₄)₂Pt(CN)₄.
D) (NH₄)₂[Pt(CN)₆].
E) NH₄[Pt(CN)₄].

Question 47

Hydrated transition metal ions produce solutions that are ________

A) acidic.
B) basic.
C) neutral.
D) strongly basic.
E) strongly acidic.

Question 48

Which ligand below is not correctly named?

A) H₂O, hydro
B) NH₃, ammine
C) CN^-, cyano
D) CO, carbonyl
E) OH^-, hydroxo

Question 49

The correct name for [Co(NH₃)₆][Cr(CN)₆] is ________

A) cobaltammine chromiumcyanide.
B) hexamminecobalt(III) hexacyanochromate (II).
C) hexamminecobaltate(III) hexacyanochromium(III).
D) hexamminecobalt(III) hexacyanochromate(III).
E) hexamminecobalt(II) hexacyanochromate(II).

Question 50

What is the equilibrium concentration of Cl^-(aq) in a solution that is 0.0200 M solution in CuNO₃ and 0.450 M HCl(aq)?
Given: Cu⁺(aq) + 3 Cl^-(aq) $\leftrightarrow$ CuCl₃^2- K_f = 5 * 10⁵.

A) 0.450 M
B) 2.0 *10^-6 M
C) 0.390 M
D) 0.430 M
E) 5 * 10⁵ M

Question 51

The correct name for K₂[CuCl₄] is ________

A) potassium copper chloride.
B) potassium tetrachlorocuprate(II).
C) dipotassium chlorocuprate(II).
D) potassium tetrachlorocopper(II).
E) dipotassium tetrachlorocopper(II).

Question 52

What is the correct formula for sodium tetracyanodihydroxovanadate(II)?

A) Na₂[V(CN)₄(OH)₂]
B) Na₃[V(CN)₄(OH)₂]
C) Na₄[V(CN)₄(OH)₂]
D) Na[V(CN)₄(OH)₂]
E) Na₃[V(CN)₄(OH)]

Question 53

Which one of the following compounds is called diamminetriaquahydroxochromium(II) nitrate?

A) [Cr(NH₃)₂(H₂O)₃(OH)](NO₃)₂
B) [Cr(NH₃)₂(H₂O)₃(OH)]NO₃
C) [Cr(NH₃)₂(H₂O)₃](OH)NO₃
D) [Cr(NH₃)₂(OH)]NO₃ • 3H₂O
E) [Cr(NH₃)₂NO₃]OH(aq)

Question 54

The correct name for the complex ion [Co(NH₃)₅Cl]²⁺ is ________

A) pentaamminechlorocobalt(III).
B) pentaamminechlorocobalt(II).
C) chloropentaamminecobalt(III).
D) pentaamminechlorocobaltate(III).
E) pentaamminechlorocobalt.

Question 55

What is the equilibrium concentration of Cu⁺(aq) in a solution that is 0.0200 M solution in CuNO₃ and 0.450 M HCl(aq)?
Given: Cu⁺(aq) + 3Cl^-(aq) $\leftrightarrow$ CuCl₃^2- K_f = 5 *10⁵.

A) 1.0 *10^-7 M
B) 6.7 *10^-7 M
C) 4.4 *10^-7 M
D) 5.0 * 10^-7 M
E) 5.0 * 10⁵ M

Question 56

The correct formula for the complex ion tetracyanoplatinate(II) is ________

A) [Pt(CN)₄²⁺].
B) [Pt(CN)₄]^2-.
C) Pt(CN)₄.
D) [Pt₂(CN)₄].
E) 4[Pt(CN)]⁺.

Question 57

Calculate the equilibrium concentration of Zn²⁺(aq) in a solution that is 0.0125 M Zn(NO₃)₂ and 0.600 M NH₃.
Given: Zn²⁺(aq) + 4 NH₃(aq) $\leftrightarrow$ Zn(NH₃)₄²⁺(aq) K_f = 2.9 * 10⁹.

A) 7.8 *10 10^-12 M
B) 4.7 *10 10^-11 M
C) 1.5 *10^-8 M
D) 2.5 * 10^-9 M
E) 2.9 * 10⁹ M

Question 58

Which is the correct formula for potassium hexacyanoferrate(II)?

A) K[Fe(CN)₂]
B) K₂[Fe(CN)₂]
C) K₃[Fe(CN)₆]
D) K₄[Fe(CN)₆]
E) K₆[Fe(CN)₆]

Question 59

For the reaction:
Fe(H₂O)₆³⁺ + H₂O(l) $\leftrightarrow$ Fe(H₂O)₅(OH)²⁺ + H₃O⁺(aq)
Fe(H₂O)₆³⁺ is a(n) ________ and water is a(n) ________.

A) acid; base
B) base; acid
C) acid; catalyst
D) catalyst; base
E) Lewis base; Lewis acid

Question 60

What is the correct formula for hexamminecobalt(III) nitrite?

A) [Co(NH₃)₆](NO₃)₃
B) Co(NH₃)₆(NO₂)₃
C) [Co(NH₃)₆](NO₂)₃
D) [Co(NH₃)₆](NO₂)₂
E) [Co(NH₃)₆](NO₃)₂

Question 61

Complex ions with different ligands have different colors because the ligands ________

A) are different colors.
B) affect the energy levels of the lone-pair electrons on the metal.
C) have different energies for their bonding electrons.
D) affect the energy levels of the metal d orbitals.
E) have different energies for their lone-pair electrons.

Question 62

CoF₆^3- absorbs light in the red region of the spectrum, while Co(NH₃)₆³⁺ absorbs light in the blue region of the spectrum. This difference means that ________

A) the splitting of the d orbitals of the two complexes is nearly identical.
B) the value of the crystal field splitting is very small for both complexes.
C) the crystal field splitting is larger for the ammonia complex than for the fluoride complex.
D) the d_z² and d_x² - _y² orbitals are higher in energy than the d_xy, d_xz, and d_yz orbitals in CoF₆^3- and just the opposite splitting order for Co(NH₃)₆³⁺.
E) the d_z² and d_x² - _y² orbitals are lower in energy than the d_xy, d_xz, and d_yz orbitals in CoF₆^3- and just the opposite splitting order for Co(NH₃)₆³⁺.

Question 63

Ethylenediamine is an example of a ________ ligand.

A) tridentate
B) hexadentate
C) bidentate
D) pentadentate
E) hydrocarbon

Question 64

Which atoms on EDTA bond to metal ions?

A) carbon and oxygen
B) carbon and nitrogen
C) oxygen and nitrogen
D) nitrogen and hydrogen
E) oxygen and hydrogen

Question 65

How many chelation sites and donor groups does EDTA have?

A) 2
B) 10
C) 6
D) 4
E) 5

Question 66

Oxalic acid is a dicarboxylic acid with the structure HOOCCOOH. How many coordination sites does the ion (OOCCOO)^2- have?

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

Question 67

The greater affinity of metal ions for polydentate ligands than for monodentate ligands is known as the ________ effect.

A) dentate
B) ligand
C) chelate
D) Lewis base
E) Lewis acid

Question 68

Crystal field theory describes ________

A) how ligands cause the metal d orbitals to have different energies.
B) the covalent bonding in transition metal complexes.
C) how d orbitals change their shapes when ligands are present.
D) how metal s, p, and d orbitals are hybridized to bond with ligands.
E) the molecular orbitals that describe the bonding in transition metal complexes.

Question 69

Which of the following is a polydentate ligand?

A) NH₃
B) OH^-
C) H₂O
D) diethylenetriamine
E) CN^-

Question 70

Aqueous solutions of many metal cations have a pH different from 7. Which one of the following statements about these cations is not correct?

A) Alkali metal cations such as Na⁺ and K⁺ have a negligible effect on the pH.
B) Small and highly charged main group metals such as Al³⁺ produce acidic aqueous solutions.
C) For transition metal cations, the cation with the higher oxidation state produces the more acidic solution; for example, Fe³⁺(aq) is more acidic than Fe²⁺(aq).
D) A solution containing Cr²⁺ is expected to be considerably more acidic than a solution of equal concentration containing Ni²⁺.
E) The Lewis acidity of a metal cation is a good measure of its ability to activate a water molecule to lose a proton and produce a hydronium ion.

Question 71

Which of the following is a chelation agent?

A) EDTA
B) Cl^-
C) NH₂
D) SCN^-
E) CN^-

Question 72

Transition metal ions often absorb visible light in promoting electrons from a ground state to an excited state. Why doesn't aluminum(III) ion have this property?

A) It does, and this fact accounts for the color of some gemstones.
B) Aluminum(III) has a noble gas configuration-that of argon.
C) Aluminum(III) has a noble gas configuration-that of neon.
D) Aluminum(III) has a filled d subshell.
E) The crystal field splitting of the d orbitals in aluminum(III) is very large.

Question 73

Which statement concerning ligands in transition metal complexes is not correct?

A) The addition of ammonia to a chloro complex should generate the corresponding ammine complex because ammonia is a stronger Lewis base than chloride.
B) Ammonia is a stronger ligand than water because ammonia is a stronger Lewis base than water.
C) All ligands are Lewis bases.
D) Cyanide is a stronger ligand than water because cyanide is a stronger Lewis base than water.
E) Cyanide is a stronger ligand than fluoride because it is composed of two atoms.

Question 74

When the five 3d orbitals on a metal ion experience an octahedral field in a complex, they split into ________ energy levels.

A) two
B) three
C) four
D) five
E) six

Question 75

A solution containing the ion CoF₆^3- has an absorption maximum at $\Delta$ _max = 680 nm. The color of this solution is ________

A) red.
B) green.
C) blue.
D) orange.
E) violet.

Question 76

Many metal cations produce aqueous solutions that have a pH different from 7. Which one of the following statements A-D about this phenomenon is not correct? If all are correct, respond E.

A) For a given metal, the cation with the higher oxidation number will produce the more acidic solution, for example, Fe³⁺(aq) is more acidic than Fe²⁺(aq).
B) The Lewis acidity of the cation is a good measure of its ability to produce an acidic solution.
C) Small highly charged main group metal cations, such as Al³⁺, produce acidic aqueous solutions.
D) Alkali metal cations, such as Na⁺ and K⁺, have a negligible effect on the pH of a solution.
E) Statements A-D are all correct.

Question 77

Co(NH₃)₆³⁺(aq) absorbs light in the blue region of the spectrum. The color of a solution containing this ion is ________

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

Question 78

Which, if any, of the following compounds form an acidic solution when dissolved in water?
I. CaCl₂
II. CrCl₃
III. NaCl
IV. FeCl₂

A) None form an acidic solution.
B) All form an acidic solution.
C) Only I and III form an acidic solution.
D) Only II and IV form an acidic solution.
E) Only I, II, and IV form an acidic solution.

Question 79

As the value of the crystal field splitting, $\Delta$ _o, increases from one complex ion to another, ________

A) the wavelength of absorbed light increases.
B) the wavelength of absorbed light decreases.
C) the number of d electrons increases.
D) the number of d electrons decreases.
E) the color of the solution shifts from red towards blue.

Question 80

EDTA is an example of a ________ ligand.

A) tridentate
B) hexadentate
C) tetradentate
D) pentadentate
E) hydrocarbon