Deck 19: Complex Ions

Question 1

What is the coordination number of the central metal ion in [Ni(NH₃)₄(H₂O)₂]Cl₂?

A) 0
B) 2
C) 4
D) 6
E) 8

Answer 1

6

Question 2

Identify the ligands and their charges in [Os(NH₃)₄Cl₂]⁺.

A) ammonia (no charge),chloride ion (charge = −1)
B) chloride ion (charge = −1)
C) ammonia (no charge)
D) osmium (charge = +3)
E) osmium (charge = +3),chloride ion (charge = −1)

Answer 2

ammonia (no charge),chloride ion (charge = −1)

Question 3

What is the formula for potassium diamminetetrachlorovanadate(III)?

A) [KV(NH₃)₂Cl₄]
B) K₂[V(NH₃)₂Cl₄]
C) K[V(NH₃)₂Cl₄]
D) [KV(NH₃)₂]Cl₄
E) K[V(NH₃)₂]Cl₄

Answer 3

K[V(NH₃)₂Cl₄]

Question 4

What is the coordination number of the copper in [Cu(NH₃)₂]Cl?

A) 1
B) 2
C) 3
D) 4
E) 8

Question 5

What is the name of the compound having the formula K₂[PtCl₄]?

A) potassium chloroplatinate(II)
B) potassium tetrachloroplatinate(II)
C) potassium chloroplatinate(IV)
D) potassium platanotetrachlorate(II)
E) dipotassium tetrachloroplatnum(II)

Question 6

What is the oxidation number of molybdenum in [Mo(H₂O)₅OH]Cl₂?

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

Question 7

A Lewis base is defined as a species that

A) increases the OH− concentration in water.
B) accepts a proton.
C) donates a pair of electrons to a bond.
D) has a negative charge.
E) is two electrons short of an octet in the valence shell.

Question 8

What is the name of the compound having the formula (NH₄)₂[Cu(CN)₄]?

A) ammonium tetracyanocuprate(II)
B) diammonium tetracyanocuprate(II)
C) bisamminetetracyanocuprate(II)
D) tetracyanobisamminecuprate(II)
E) tetracyanocuprate(II)ammonia

Question 9

What is the coordination number of the central metal ion in [Cr(en)₂(OH)₂]NO₃? (en = H₂NCH₂CH₂NH₂)

A) 0
B) 2
C) 4
D) 6
E) 7

Question 10

What is the correct formula for a nickel(II)complex which contains 4 ammonia molecules and 2 water molecules?

A) Ni(NH₃)₄(H₂O)₂
B) Ni(NH₃)₄(H₂O)₂²⁺
C) [Ni(NH₃)₄](H₂O)₂
D) Ni(NH₃)₄(H₂O)₂²⁻
E) Ni(NH₃)₄(H₂O)₂⁴⁻

Question 11

What is the correct formula for a square planar copper(II)complex that is bonded to ethylenediamine ligands?

A) Cu(en)²⁺
B) Cu(en)₂²⁺
C) Cu(en)₃²⁺
D) Cu(en)₄²⁺
E) Cu(en)₆²⁺

Question 12

What is the oxidation number of the iron in [Fe(CN)₆]³⁻?

A) −3
B) −2
C) +2
D) +3
E) +4

Question 13

What is the formula for dicyanobis(ethylenediamine)zirconium(IV)nitrate?

A) Zr[(CN)₂(NO₃)₂(en)₂]
B) [Zr(CN)₂(NO₃)₂(en)₂]
C) (NO₃)₂[Zr(CN)₂(en)₂]
D) [Zr(CN)₂(en)₂](NO₃)₂
E) [Zr(NO₃)₂(en)₂](CN)₂

Question 14

What is the oxidation number of the chromium in [Cr(H₂O)₂Cl₄]−?

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

Question 15

Which molecule or ion does NOT act as a ligand?

A) H₂O
B) NH₄⁺
C) Cl^-
D) C₂O₄^2-
E) CN^-

Question 16

Identify the ligands and their charges in [Co(en)₂Br₂]⁺.

A) ethylene (charge = −1),bromide (charge = 0)
B) ethylene (charge = −1),bromide ion (charge = −1)
C) ethylenediamine (charge = 0),bromide ion (charge = −1),cobalt (charge = +3)
D) ethylenediamine (charge = 0),bromide (charge = 0)
E) ethylenediamine (charge = 0),bromide ion (charge = −1)

Question 17

Identify the ligands and their charges in [Cr(en)₄(CN)₂]NO₃.

A) ethylenediamine (no charge)
B) cyanide (charge = no charge)
C) nitrate ion (charge = −1)
D) ethylenediamine (no charge),cyanide ion (charge = −1)
E) ethylenediamine (no charge),cyanide ion (charge = −1),nitrate ion (charge = −1)

Question 18

What is the oxidation number of the copper in [Cu(NH₃)₃Cl]NO₃?

A) 0
B) +1
C) +2
D) +4
E) +5

Question 19

Ions such as [Co(H₂O)₆]³⁺ and [Ag(CN)₂]^- are called ____.

A) ligands
B) Lewis bases
C) chelates
D) alloys
E) coordination complexes

Question 20

What is the name of the compound having the formula [Cr(en)₂(H₂O)₂]SO₄?

A) dihydroxydiethlyenediamminechromate(II)sulfate
B) diaquabis(ethylenediamine)sulfatochromate(IV)
C) bis(ethylenediamine)diaquachromium(II)sulfato
D) diaquabis(ethylenediamine)sulfatochromium(II)
E) diaquabis(ethylenediamine)chromium(II)sulfate

Question 21

The complex FeF₆⁴⁻ is paramagnetic.Which of the following set of terms best describes the complex?

A) high-spin,Δ_o large
B) high-spin,Δ_o small
C) low-spin,Δ_o large
D) low-spin,Δ_o small
E) none of the above

Question 22

If an octahedral iron(II)complex is diamagnetic,which of the following sets of conditions best describes the complex?

A) low-spin,Δ_o small
B) low-spin,Δ_o large
C) high-spin,Δ_o small
D) high-spin,Δ_o large
E) none of these

Question 23

Which of the following species have geometric isomers: [Fe(en)Cl₄]^-,[Fe(en)₂Cl₂]⁺,and [Fe(en)₂BrCl]⁺?

A) [Fe(en)Cl₄]^- only
B) [Fe(en)₂Cl₂]⁺ only
C) [Fe(en)₂BrCl]⁺ only
D) [Fe(en)₂Cl₂]⁺ and [Fe(en)₂BrCl]⁺
E) [Fe(en)Cl₄]^-,[Fe(en)₂Cl₂]⁺,and [Fe(en)₂BrCl]⁺

Question 24

Potassium hexacyanoiron(II),K₄[Fe(CN)₆],is water soluble.In an aqueous solution,it will decompose into

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

Question 25

How many geometric isomers may exist for the square-planar complex ion [Pt(OH)₂(NH₃)₂]^2-?

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

Question 26

What are the possible formulas of all the tetracoordinate complex ions formed by copper(II)with NH₃ and/or ethylenediamine (en)molecules as ligands?

A) Cu(NH₃)₄²⁺,Cu(en)(NH₃)₃²⁺,Cu(en)₂(NH₃)₂²⁺,Cu(en)₃(NH₃)²⁺,Cu(en)₄²⁺
B) Cu(NH₃)₄²⁺,Cu(en)₂(NH₃)₄²⁺,Cu(en)₂²⁺
C) Cu(NH₃)₄²⁺,Cu(en)(NH₃)₂²⁺,Cu(en)₂²⁺
D) Cu(NH₃)₆²⁺,Cu(en)₂(NH₃)₂²⁺,Cu(en)₃²⁺
E) Cu(NH₃)₄²⁺,Cu(en)₂²⁺

Question 27

Determine the number of unpaired electrons in an octahedral,strong-field Mn²⁺ complex ion.

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

Question 28

How many geometric isomers exist for [Fe(H₂O)₄(NH₃)₂]³⁺?

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

Question 29

All of the followings statements are true EXCEPT

A) transition metal complexes are often colored,due to 3d to 1s electronic transitions.
B) in low-spin complexes,electrons are concentrated in the lower-energy orbitals.
C) low-spin complexes contain the minimum number of unpaired electrons.
D) the crystal field splitting energy is small in high-spin complexes.
E) the crystal field splitting energy of a metal complex can sometimes be determined from the absorption spectrum.

Question 30

Chlorophylls are coordination compounds that contain a magnesium ion as the central metal.The most abundant chlorophyll,called chlorophyll a,has a mass percent of magnesium of 2.72%.What is the molar mass of chlorophyll a?

A) 2.72 g/mol
B) 57.2 g/mol
C) 112 g/mol
D) 583 g/mol
E) 893 g/mol

Question 31

Which of the following molecules or ions are chelating agents: NH₃,H₂NCH₂CH₂NH₂,CO₂,and C₂O₄²⁻?

A) NH₃
B) NH₃ and CO₂
C) CO₂ and H₂NCH₂CH₂NH₂
D) H₂NCH₂CH₂NH₂ and C₂O₄²⁻
E) CO₂,H₂NCH₂CH₂NH₂ and C₂O₄²⁻

Question 32

What is the electron configuration of Cr²⁺?

A) 1s²2s²2p⁶3s²3p⁶
B) 1s²2s²2p⁶3s²3p⁶3d⁶4s²
C) 1s²2s²2p⁶3s²3p⁶3d³4s²
D) 1s²2s²2p⁶3s²3p⁶3d⁵4s¹
E) 1s²2s²2p⁶3s²3p⁶3d⁴

Question 33

What is the electron configuration for Fe³⁺?

A) 1s²2s²2p⁶3s²3p⁶3d⁵4s¹
B) 1s²2s²2p⁶3s²3p⁶3d⁴4s²
C) 1s²2s²2p⁶3s²3p⁶3d⁶
D) 1s²2s²2p⁶3s²3p⁶3d⁵
E) 1s²2s²2p⁶3s²3p⁶3d⁷

Question 34

How many possible structures exist for the tetrahedral complex [Zn(en)₃]²⁺?

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

Question 35

How many geometric isomers exist for [Fe(en)₂(CN)₂]⁺?

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

Question 36

What is the electron configuration for Ti⁴⁺?

A) 1s²2s²2p⁶3s²3p⁶4s²
B) 1s²2s²2p⁶3s²3p⁶3d²
C) 1s²2s²2p⁶3s²3p⁶3d²4s²
D) 1s²2s²2p⁶3s²3p⁶3d¹⁰
E) 1s²2s²2p⁶3s²3p⁶

Question 37

Determine the number of unpaired electrons in the low-spin complex ion Cr(CN)₆⁴⁻.

A) 0
B) 1
C) 2
D) 4
E) 5

Question 38

Determine the number of unpaired electrons in an octahedral,high-spin Cr(II)complex.

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

Question 39

When 6 ligands approach a central metal atom along the x-,y- and z-axes,they will cause the d orbitals to split in energy.The and the orbitals are most affected because

A) the electron density in these orbitals is squared.
B) unlike the other d orbitals,these orbitals contain unpaired electrons and absorb the energy of light more readily,compared to the other three d orbitals.
C) unlike the other d orbitals,these orbitals each contain a pair of electrons.
D) they have the highest electron density along the x-,y-,and z-axes,and thus feel the greatest repulsion from the ligands' unpaired electrons.
E) the shape of these orbitals is similar to that of the ligands' orbitals.

Question 40

All of the following statements concerning crystal field theory are true EXCEPT

A) in low-spin complexes,electrons are concentrated in the d_xy,d_yz,and d_xz orbitals.
B) in an isolated atom or ion,the five d orbitals have identical energy.
C) low-spin complexes contain the maximum number of unpaired electrons.
D) the crystal field splitting is larger in low-spin complexes than high-spin complexes.
E) the energy difference between d orbitals often corresponds to an energy of visible light.

Question 41

Which of the following ligands causes the smallest splitting of d orbitals?

A) Cl−
B) en
C) CN−
D) NH₃
E) NO₃−

Question 42

Heme is a coordination compound essential to your life.What is the metal ion coordinated in the heme of hemoglobin?

A) Cu²⁺
B) Ca²⁺
C) Co²⁺
D) Fe²⁺
E) Mg²⁺

Question 43

Ti(NH₃)₆³⁺ has a d-orbital electron transition at 399 nm.Find Δ_o at this wavelength.

A) 300 kJ/mol
B) 235 kJ/mol
C) 499 kJ/mol
D) 399 kJ/mol
E) 150 kJ/mol

Question 44

The spectrochemical series

A) lists metals ions in order of their oxidation state.
B) lists metals ions in order by their color.
C) lists ligands in order of their tendency to split d orbitals.
D) is used to determine the oxidation state of a central metal atom.
E) is used to calculate the crystal field splitting energy of complex ions.

Question 45

The crystal field splitting energy for TiF₆³⁻ is 203 kJ/mol.At what wavelength does the maximum absorbance of light occur for this complex?

A) 9.80 × 10−³¹ nm
B) 9.80 × 10−²⁸ nm
C) 4.32 × 10² nm
D) 5.90 × 10² nm
E) 1.02 × 10³ nm

Question 46

The wavelength of maximum absorption of Cu(NH₃)₄²⁺ is 5.80 × 10² nm.What is the energy of the electronic transition?

A) 3.80 × 10−³⁶ J
B) 1.16 × 10−³¹ J
C) 1.16 × 10−²² J
D) 3.42 × 10−¹⁹ J
E) 2.63 × 10⁺³⁵ J

Question 47

Which of the following ligands causes the greatest splitting of d orbitals?

A) H₂O
B) NO₂−
C) Cl−
D) F−
E) NH₃

Question 48

Alfred Werner published his theory of coordination chemistry in 1893.One of the postulates of his theory was that coordination complexes have "primary valences" and "secondary valences." He showed this by testing the ____ of solutions containing [Co(NH₃)₆]Cl₃ vs.[Co(NH₃)₅ Cl]Cl₂ vs.[Co(NH₃)₄ Cl₂]Cl.

A) color
B) conductivity
C) density
D) melting point
E) taste

Question 49

All of the following ions are able to form both low-spin and high-spin octahedral complex ions EXCEPT

A) Cr²⁺.
B) Cr³⁺.
C) Mn²⁺.
D) Fe³⁺.
E) Co³⁺.

Question 50

Why might a cyano complex of a metal appear yellow and the chloride complex of the same metal appear green?

A) The cyanide ions transmits yellow light more efficiently than the chloride ions.
B) The cyanide ions splits the d orbital energies more than the chloride ions,resulting in the cyanide complex absorbing yellow light.
C) The cyanide ions splits the d orbital energies more than chloride ions,resulting in the absorption band for the cyanide complex being shifted to shorter wavelengths.
D) The chloride ions splits the d orbital energies more than cyanide ions,resulting in the absorption band for the chloride complex being shifted to shorter wavelengths.
E) The chloride ions splits the d orbital energies more than the cyanide ions,resulting in the chloride complex absorbing yellow light.

Question 51

All of the following complexes will be colored (in the visible)EXCEPT ____.

A) [Co(en)₃]²⁺
B) [Fe(CN)₆]^4-
C) [Ni(H₂O)₆]²⁺
D) [Sc(NH₃)₆]³⁺
E) [Cu(NH₃)₄]²⁺