A certain first-row transition metal ion forms many different colored solutions. When

Give the systematic name for each of the following coordination compounds. a. [Co(NH3)5Cl]Cl2 b. K3Fe(CN)6 c. [Fe(en)2(NO2)2]2SO4

Given the following systematic names, give the formula of each coordination compound. a. Triamminebromoplatinum(II) chloride b. Potassium hexafluorocobaltate(III)

Does the complex ion [Co(NH3)Br(en)2]21 exhibit geometrical isomerism? Does it exhibit optical isomerism?

What if you are told the number of unpaired electrons for a coordinate covalent ion and are asked to tell if the ligand produced a strong or weak field? Give an example of a coordinate covalent ion for which you could decide if it produced a strong or weak field and one for which you couldnt, and explain your answers.

The Fe(CN)6 32 ion is known to have one unpaired electron. Does the CN2 ligand produce a strong or weak field?

Predict the number of unpaired electrons in the complex ion Cr(CN)6 42

Give the crystal field diagram for the tetrahedral complex ion CoCl4 22

Figure 21.28(a) shows a crystal field diagram for a square planar complex oriented in the xy plane. What if you oriented the complex in the xz plane? Sketch the crystal field diagram and contrast it with Fig. 21.28(a).

What two first-row transition metals have unexpected electron configurations? A statement in the text says that first-row transition metal ions do not have 4s electrons. Why not? Why do transition metal ions often have several oxidation states, whereas representative metals generally have only one?

Define each of the following terms: a. coordination compound b. complex ion c. counterions d. coordination number e. ligand f. chelate g. bidentate How would transition metal ions be classified using the Lewis definition of acids and bases? What must a ligand have to bond to a metal? What do we mean when we say that a bond is a coordinate covalent bond?

When a metal ion has a coordination number of 2, 4, or 6, what are the observed geometries and associated bond angles? For each of the following, give the correct formulas for the complex ions. a. linear Ag1 complex ions having CN2 ligands b. tetrahedral Cu1 complex ions having H2O ligands c. tetrahedral Mn21 complex ions having oxalate ligands d. square planar Pt21 complex ions having NH3 ligands e. octahedral Fe31 complex ions having EDTA ligands f. octahedral Co21 complex ions having Cl2 ligands g. octahedral Cr31 complex ions having ethylenediamine ligands What is the electron configuration for the metal ion in each of the complex ions in ag?

What is wrong with the following formulaname combinations? Give the correct names for each. a. [Cu(NH3)4]Cl2 copperammine chloride b. [Ni(en)2]SO4 bis(ethylenediamine)nickel(IV) sulfate c. K[Cr(H2O)2Cl4] potassium tetrachlorodiaquachromium(III) d. Na4[Co(CN)4C2O4] tetrasodium tetracyanooxalatocobaltate(II)

Define each of the following and give examples of each. a. isomer b. structural isomer c. stereoisomer d. coordination isomer e. linkage isomer f. geometrical isomer g. optical isomer Consider the cis and trans forms of the octahedral complex Cr(en)2Cl2. Are both of these isomers optically active? Explain. Another way to determine whether a substance is optically active is to look for a plane of symmetry in the molecule. If a substance has a plane of symmetry, then it will not exhibit optical activity (the mirror image will be superimposable). Show the plane of symmetry in the trans isomer and prove to yourself that the cis isomer does not have a plane of symmetry

What is the major focus of the crystal field model? Why are the d orbitals split into two sets for an octahedral complex? What are the two sets of orbitals? Define each of the following. a. weak-field ligand b. strong-field ligand c. low-spin complex d. high-spin complex Why is Co(NH3)6 31 diamagnetic whereas CoF6 32 is paramagnetic? Some octahedral complex ions have the same d-orbital splitting diagrams whether they are high-spin or low-spin. For which of the following is this true? a. V31 b. Ni21 c. Ru21

The crystal field model predicts magnetic properties of complex ions and explains the colors of these complex ions. How? Solutions of [Cr(NH3)6]Cl3 are yellow, but Cr(NH3)6 31 does not absorb yellow light. Why? What color light is absorbed by Cr(NH3)6 31? What is the spectrochemical series, and how can the study of light absorbed by various complex ions be used to develop this series? Would you expect Co(NH3)6 21 to absorb light of a longer or shorter wavelength than Co(NH3)6 31? Explain.

Why do tetrahedral complex ions have a different crystal field diagram than octahedral complex ions? What is the tetrahedral crystal field diagram? Why are virtually all tetrahedral complex ions high spin? Explain the crystal field diagram for square planar complex ions and for linear complex ions.

Review Table 21.18, which lists some important biological functions associated with different first-row transition metals. The transport of O2 in the blood is carried out by hemoglobin. Briefly explain how hemoglobin transports O2 in the blood.

Define and give an example of each of the following. a. roasting b. smelting c. flotation d. leaching e. gangue What are the advantages and disadvantages of hydrometallurgy? Describe the process by which a metal is purified by zone refining.

You isolate a compound with the formula PtCl4 ? 2KCl. From electrical conductance tests of an aqueous solution of the compound, you find that three ions per formula unit are present, and you also notice that addition of AgNO3 does not cause a precipitate. Give the formula for this compound that shows the complex ion present. Explain your findings. Name this compound

Both Ni(NH3)4 21 and Ni(SCN)4 22 have four ligands. The first is paramagnetic, and the second is diamagnetic. Are the complex ions tetrahedral or square planar? Explain

Which is more likely to be paramagnetic, Fe(CN)6 42 or Fe(H2O)6 21? Explain.

A metal ion in a high-spin octahedral complex has two more unpaired electrons than the same ion does in a low-spin octahedral complex. Name some possible metal ions for which this would be true.

What is the lanthanide contraction? How does the lanthanide contraction affect the properties of the 4d and 5d transition metals?

Four different octahedral chromium coordination compounds exist that all have the same oxidation state for chromium and have H2O and Cl2 as the ligands and counterions. When 1 mole of each of the four compounds is dissolved in water, how many moles of silver chloride will precipitate upon addition of excess AgNO3?

Figure 21.17 shows that the cis isomer of Co(en)2Cl2 1 is optically active while the trans isomer is not optically active. Is the same true for Co(NH3)4Cl2 1? Explain.

A certain first-row transition metal ion forms many different colored solutions. When four coordination compounds of this metal, each having the same coordination number, are dissolved in water, the colors of the solutions are red, yellow, green, and blue. Further experiments reveal that two of the complex ions are paramagnetic with four unpaired electrons and the other two are diamagnetic. What can be deduced from this information about the four coordination compounds?

Oxalic acid is often used to remove rust stains. What properties of oxalic acid allow it to do this?

For the following crystal field diagrams, label each as low spin, high spin, or cannot tell. Explain your answers. (a) (b) (c

CoCl4 22 forms a tetrahedral complex ion and Co(CN)6 32 forms an octahedral complex ion. What is wrong about the following statements concerning each complex ion and the d orbital splitting diagrams? a. CoCl4 22 is an example of a strong-field case having two unpaired electrons. b. Because CN2 is a weak-field ligand, Co(CN)6 32 will be a low-spin case having four unpaired electrons

The following statements discuss some coordination compounds. For each coordination compound, give the complex ion and the counterions, the electron configuration of the transition metal, and the geometry of the complex ion. a. CoCl2 ? 6H2O is a compound used in novelty devices that predict rain. b. During the developing process of black-and-white film, silver bromide is removed from photographic film by the fixer. The major component of the fixer is sodium thiosulfate. The equation for the reaction is: AgBr1s2 1 2Na2S2O3 1aq2 h Na3 3Ag1S2O32 2 4 1aq2 1 NaBr1aq2 c. In the production of printed circuit boards for the electronics industry, a thin layer of copper is laminated onto an insulating plastic board. Next, a circuit pattern made of a chemically resistant polymer is printed on the board. The unwanted copper is removed by chemical etching, and the protective polymer is finally removed by solvents. One etching reaction is: Cu1NH32 4Cl2 1aq2 1 4NH3 1aq2 1 Cu1s2 h 2Cu1NH32 4Cl1aq2 Assume these copper complex ions have tetrahedral geometry.

When concentrated hydrochloric acid is added to a red solution containing the Co(H2O)6 21 complex ion, the solution turns blue as the tetrahedral CoCl4 22 complex ion forms. Explain this color change.

Tetrahedral complexes of Co21 are quite common. Use a d-orbital splitting diagram to rationalize the stability of Co21 tetrahedral complex ions

Which of the following ligands are capable of linkage isomerism? Explain your answer. SCN2, N3 2, NO2 2, NH2CH2CH2NH2, OCN2, I2

Compounds of copper(II) are generally colored, but compounds of copper(I) are not. Explain. Would you expect Cd(NH3)4Cl2 to be colored? Explain.

Compounds of Sc31 are not colored, but those of Ti31 and V31 are. Why?

Almost all metals in nature are found as ionic compounds in ores instead of being in the pure state. Why? What must be done to a sample of ore to obtain a metal substance that has desirable properties?

What causes high-altitude sickness, and what is high-altitude acclimatization?

Why are CN2 and CO toxic to humans?

Write electron configurations for the following metals. a. Ni b. Cd c. Zr d. Os

Write electron configurations for the following ions. a. Ni21 c. Zr31 and Zr41 b. Cd21 d. Os21 and Os31

Write electron configurations for each of the following. a. Ti, Ti21, Ti41 b. Re, Re21, Re31 c. Ir, Ir21, Ir31

Write electron configurations for each of the following. a. Cr, Cr21, Cr31 b. Cu, Cu1, Cu21 c. V, V21, V31

What is the electron configuration for the transition metal ion in each of the following compounds? a. K3[Fe(CN)6] b. [Ag(NH3)2]Cl c. [Ni(H2O)6]Br2 d. [Cr(H2O)4(NO2)2]I

What is the electron configuration for the transition metal ion(s) in each of the following compounds? a. (NH4)2[Fe(H2O)2Cl4] b. [Co(NH3)2(NH2CH2CH2NH2)2]I2 c. Na2[TaF7] d. [Pt(NH3)4I2][PtI4] Pt forms 12 and 14 oxidation states in compounds

Molybdenum is obtained as a by-product of copper mining or is mined directly (primary deposits are in the Rocky Mountains in Colorado). In both cases it is obtained as MoS2, which is then converted to MoO3. The MoO3 can be used directly in the production of stainless steel for high-speed tools (which accounts for about 85% of the molybdenum used). Molybdenum can be purified by dissolving MoO3 in aqueous ammonia and crystallizing ammonium molybdate. Depending on conditions, either (NH4)2Mo2O7 or (NH4)6Mo7O24 ? 4H2O is obtained. a. Give names for MoS2 and MoO3. b. What is the oxidation state of Mo in each of the compounds mentioned above?

Titanium dioxide, the most widely used white pigment, occurs naturally but is often colored by the presence of impurities. The chloride process is often used in purifying rutile, a mineral form of titanium dioxide. a. Show that the unit cell for rutile, shown below, conforms to the formula TiO2. (Hint: Recall the discussion in Sections 10.4 and 10.7.)b. The reactions for the chloride process are 2TiO2 1s2 1 3C1s2 1 4Cl2 1g2 888n 2TiCl4 1g2 1 CO2 1g2 1 2CO1g2 TiCl4 1g2 1 O2 1g2 8888888n TiO2 1s2 1 2Cl2 1g2 Assign oxidation states to the elements in both reactions. Which elements are being reduced, and which are being oxidized? Identify the oxidizing agent and the reducing agent in each reaction.

When 6 M ammonia is added gradually to aqueous copper(II) nitrate, a white precipitate forms. The precipitate dissolves as more 6 M ammonia is added. Write balanced equations to explain these observations. [Hint: Cu21 reacts with NH3 to form Cu(NH3)4 21.]

When an aqueous solution of KCN is added to a solution containing Ni21 ions, a precipitate forms, which redissolves on addition of more KCN solution. Write reactions describing what happens in this solution. [Hint: CN2 is a BrnstedLowry base 1Kb < 1025 2 and a Lewis base.]

Consider aqueous solutions of the following coordination compounds: Co(NH3)6I3, Pt(NH3)4I4, Na2PtI6, and Cr(NH3)4I3. If aqueous AgNO3 is added to separate beakers containing solutions of each coordination compound, how many moles of AgI will precipitate per mole of transition metal present? Assume that each transition metal ion forms an octahedral complex.

A coordination compound of cobalt(III) contains four ammonia molecules, one sulfate ion, and one chloride ion. Addition of aqueous BaCl2 solution to an aqueous solution of the compound gives no precipitate. Addition of aqueous AgNO3 to an aqueous solution of the compound produces a white precipitate. Propose a structure for this coordination compound.

Name the following complex ions: a. Mn NC CN 4 NC CN CN CN b. H3N Co H3N + Cl NH3 Cl NH3 c. H3N Co H3N + NH3 Cl NH3 NH3

Name the following complex ions. a. Ru(NH3)5Cl21 e. Ni(CN)4 22 b. Fe(CN)6 42 f. Cr(NH3)4Cl2 1 c. Mn(NH2CH2CH2NH2)3 21 g. Fe(C2O4)3 32 d. Co(NH3)5NO2 21 h. Co(SCN)2(H2O)4 1

Name the following coordination compounds. a. [Co(NH3)6]Cl2 d. K4[PtCl6] b. [Co(H2O)6]I3 e. [Co(NH3)5Cl]Cl2 c. K2[PtCl4] f. [Co(NH3)3(NO2)3]

Name the following coordination compounds. a. [Cr(H2O)5Br]Br2 c. [Fe(NH2CH2CH2NH2)2(NO2)2]Cl b. Na3[Co(CN)6] d. [Pt(NH3)4I2][PtI4]

Give formulas for the following. a. potassium tetrachlorocobaltate(II) b. aquatricarbonylplatinum(II) bromide c. sodium dicyanobis(oxalato)ferrate(III) d. triamminechloroethylenediaminechromium(III) iodide

Give formulas for the following complex ions. a. tetrachloroferrate(III) ion b. pentaammineaquaruthenium(III) ion c. tetracarbonyldihydroxochromium(III) ion d. amminetrichloroplatinate(II) ion

Draw geometrical isomers of each of the following complex ions. a. Co(C2O4)2(H2O)2 2 c. Ir(NH3)3Cl3 b. Pt(NH3)4I2 21 d. Cr(en)(NH3)2I2 1

Draw structures of each of the following. a. cis-dichloroethylenediamineplatinum(II) b. trans-dichlorobis(ethylenediamine)cobalt(II) c. cis-tetraamminechloronitrocobalt(III) ion d. trans-tetraamminechloronitritocobalt(III) ion e. trans-diaquabis(ethylenediamine)copper(II) ion

The carbonate ion (CO3 22) can act as either a monodentate or a bidentate ligand. Draw a picture of CO3 22 coordinating to a metal ion as a monodentate and as a bidentate ligand. The carbonate ion can also act as a bridge between two metal ions. Draw a picture of a CO3 22 ion bridging between two metal ions

Amino acids can act as ligands toward transition metal ions. The simplest amino acid is glycine (NH2CH2CO2H). Draw a structure of the glycinate anion (NH2CH2CO2 2) acting as a bidentate ligand. Draw the structural isomers of the square planar complex Cu(NH2CH2CO2)2.

How many bonds could each of the following chelating ligands form with a metal ion? a. acetylacetone (acacH), a common ligand in organometallic catalysts: CH3 C CH2 C O CH3 O b. diethylenetriamine, used in a variety of industrial processes: NH2iCH2iCH2iNHiCH2iCH2iNH2 c. salen, a common ligand for chiral organometallic catalysts: HOOH N N d. porphine, often used in supermolecular chemistry as well as catalysis; biologically, porphine is the basis for many different types of porphyrin-containing proteins, including heme proteins:

BAL is a chelating agent used in treating heavy metal poisoning. It acts as a bidentate ligand. What type of linkage isomers are possible when BAL coordinates to a metal ion? CH2 CH2 CH SH SH OH BAL

Draw all geometrical and linkage isomers of Co(NH3)4(NO2)2.

Draw all geometrical and linkage isomers of square planar Pt(NH3)2(SCN)2.

Acetylacetone, abbreviated acacH, is a bidentate ligand. It loses a proton and coordinates as acac2, as shown below, where M is a transition metal: M O C CH3 CH CH3 O C Which of the following complexes are optically active: cisCr(acac)2(H2O)2, trans-Cr(acac)2(H2O)2, and Cr(acac)3?

Draw all geometrical isomers of Pt(CN)2Br2(H2O)2. Which of these isomers has an optical isomer? Draw the various optical isomers.

Match the crystal field diagrams given below with the following complex ions. Cr(NH3)5Cl21 Co(NH3)4Br2 1 Fe(H2O)6 31 (assume strong field) (assume weak field) (a) (b) (c)

Match the crystal field diagrams given below with the following complex ions. Fe(CN)6 32 Mn(H2O)6 21 (a) (b)

Draw the d-orbital splitting diagrams for the octahedral complex ions of each of the following. a. Fe21 (high and low spin) b. Fe31 (high spin) c. Ni21

Draw the d-orbital splitting diagrams for the octahedral complex ions of each of the following. a. Zn21 b. Co21 (high and low spin) c. Ti31

The CrF6 42 ion is known to have four unpaired electrons. Does the F2 ligand produce a strong or weak field?

The Co(NH3)6 31 ion is diamagnetic, but Fe(H2O)6 21 is paramagnetic. Explain.

How many unpaired electrons are in the following complex ions? a. Ru(NH3)6 21 (low-spin case) b. Ni(H2O)6 21 c. V(en)3 31

The complex ion Fe(CN)6 32 is paramagnetic with one unpaired electron. The complex ion Fe(SCN)6 32 has five unpaired electrons. Where does SCN2 lie in the spectrochemical series relative to CN2?

Rank the following complex ions in order of increasing wavelength of light absorbed. Co1H2O2 6 31, Co1CN2 6 32, CoI6 32, Co1en2 3 31

The complex ion Cu(H2O)6 21 has an absorption maximum at around 800 nm. When four ammonias replace water, Cu(NH3)4(H2O)2 21, the absorption maximum shifts to around 600 nm. What do these results signify in terms of the relative field splittings of NH3 and H2O? Explain.

The following test tubes each contain a different chromium complex ion. Photo Cengage Learning. All rights reserved For each complex ion, predict the predominant color of light absorbed. If the complex ions are Cr(NH3)6 31, Cr(H2O)6 31, and Cr(H2O)4Cl2 1, what is the identity of the complex ion in each test tube? (Hint: Reference the spectrochemical series.)

Consider the complex ions Co(NH3)6 31, Co(CN)6 32, and CoF6 32. The wavelengths of absorbed electromagnetic radiation for these compounds (in no specific order) are 770 nm, 440 nm, and 290 nm. Match the complex ion to the wavelength of absorbed electromagnetic radiation

The wavelength of absorbed electromagnetic radiation for CoBr4 22 is 3.4 3 1026 m. Will the complex ion CoBr6 42 absorb electromagnetic radiation having a wavelength longer or shorter than 3.4 3 1026 m? Explain.

The complex ion NiCl4 22 has two unpaired electrons, whereas Ni(CN)4 22 is diamagnetic. Propose structures for these two complex ions

How many unpaired electrons are present in the tetrahedral ion FeCl4 2?

The complex ion PdCl4 22 is diamagnetic. Propose a structure for PdCl4 22.

A blast furnace is used to reduce iron oxides to elemental iron. The reducing agent for this reduction process is carbon monoxide. a. Given the following data: Fe2O3 1s2 1 3CO1g2 h 2Fe1s2 1 3CO2 1g2 DH 5 223 kJ 3Fe2O3 1s2 1 CO1g2 h 2Fe3O4 1s2 1 CO2 1g2 DH 5 239 kJ Fe3O4 1s2 1 CO1g2 h 3FeO1s2 1 CO2 1g2 DH 5 18 kJ determine DH8 for the reaction FeO1s2 1 CO1g2 h Fe1s2 1 CO2 1g2 b. The CO2 produced in a blast furnace during the reduction process actually can oxidize iron into FeO. To eliminate this reaction, excess coke is added to convert CO2 into CO by the reaction CO2 1g2 1 C1s2 h 2CO1g2 Using data from Appendix 4, determine DH8 and DS8 for this reaction. Assuming DH8 and DS8 do not depend on temperature, at what temperature is the conversion reaction of CO2 into CO spontaneous at standard conditions?

Use the data in Appendix 4 for the following. a. Calculate DH8 and DS8 for the reaction 3Fe2O3 1s2 1 CO1g2 h 2Fe3O4 1s2 1 CO2 1g2 that occurs in a blast furnace. b. Assume that DH8 and DS8 are independent of temperature. Calculate DG8 at 800.8C for this reaction.

Iron is present in the earths crust in many types of minerals. The iron oxide minerals are hematite (Fe2O3) and magnetite (Fe3O4). What is the oxidation state of iron in each mineral? The iron ions in magnetite are a mixture of Fe21 and Fe31 ions. What is the ratio of Fe31 to Fe21 ions in magnetite? The formula for magnetite is often written as FeO ? Fe2O3. Does this make sense? Explain.

What roles do kinetics and thermodynamics play in the effect that the following reaction has on the properties of steel? 3Fe 1 CmFe3C

Silver is sometimes found in nature as large nuggets; more often it is found mixed with other metals and their ores. Cyanide ion is often used to extract the silver by the following reaction that occurs in basic solution: Ag1s2 1 CN2 1aq2 1 O2 1g2 hBasic Ag1CN2 2 2 1aq2 Balance this equation by using the half-reaction method

One of the classic methods for the determination of the manganese content in steel involves converting all the manganese to the deeply colored permanganate ion and then measuring the absorption of light. The steel is first dissolved in nitric acid, producing the manganese(II) ion and nitrogen dioxide gas. This solution is then reacted with an acidic solution containing periodate ion; the products are the permanganate and iodate ions. Write balanced chemical equations for both of these steps

Acetylacetone (see Exercise 43, part a), abbreviated acacH, is a bidentate ligand. It loses a proton and coordinates as acac2, as shown below: M O C CH3 CH CH3 O C Acetylacetone reacts with an ethanol solution containing a salt of europium to give a compound that is 40.1% C and 4.71% H by mass. Combustion of 0.286 g of the compound gives 0.112 g Eu2O3. Assuming the compound contains only C, H, O, and Eu, determine the formula of the compound formed from the reaction of acetylacetone and the europium salt. (Assume that the compound contains one europium ion.)

The compound cisplatin, Pt(NH3)2Cl2, has been studied extensively as an antitumor agent. The reaction for the synthesis of cisplatin is: K2PtCl4 1aq2 1 2NH3 1aq2 h Pt1NH32 2Cl2 1s2 1 2KCl1aq2 Write the electron configuration for platinum ion in cisplatin. Most d8 transition metal ions exhibit square planar geometry. With this and the name in mind, draw the structure of cisplatin.

Use standard reduction potentials to calculate %, DG8, and K (at 298 K) for the reaction that is used in production of gold: 2Au1CN2 2 2 1aq2 1 Zn1s2 h 2Au1s2 1 Zn1CN2 4 22 1aq2 The relevant half-reactions are Au1CN2 2 2 1 e2 h Au 1 2CN2 % 5 20.60 V Zn1CN2 4 22 1 2e2 h Zn 1 4CN2 % 5 21.26 V

Until the discoveries of Alfred Werner, it was thought that carbon had to be present in a compound for it to be optically active. Werner prepared the following compound containing OH2 ions as bridging groups and separated the optical isomers. a. Draw structures of the two optically active isomers of this compound. b. What are the oxidation states of the cobalt ions? c. How many unpaired electrons are present if the complex is the low-spin case? H Co Co(NH3 H )4 O O Cl6 ( )3

Draw all the geometrical isomers of Cr(en)(NH3)2BrCl1. Which of these isomers also have an optical isomer? Draw the various isomers.

A compound related to acetylacetone is 1,1,1-trifluoroacetylacetone (abbreviated Htfa): CF3CCH2CCH3 O O Htfa forms complexes in a manner similar to acetylacetone. (See Exercise 47.) Both Be21 and Cu21 form complexes with tfa2 having the formula M(tfa)2. Two isomers are formed for each metal complex. a. The Be21 complexes are tetrahedral. Draw the two isomers of Be(tfa)2. What type of isomerism is exhibited by Be(tfa)2? b. The Cu21 complexes are square planar. Draw the two isomers of Cu(tfa)2. What type of isomerism is exhibited by Cu(tfa)2?

Would it be better to use octahedral Ni21 complexes or octahedral Cr21 complexes to determine whether a given ligand is a strong-field or weak-field ligand by measuring the number of unpaired electrons? How else could the relative ligand field strengths be determined?

Name the following coordination compounds. a. Na4[Ni(C2O4)3] b. K2[CoCl4] c. [Cu(NH3)4]SO4 d. [Co(en)2(SCN)Cl]Cl

Give formulas for the following. a. hexakis(pyridine)cobalt(III) chloride b. pentaammineiodochromium(III) iodide c. tris(ethylenediamine)nickel(II) bromide d. potassium tetracyanonickelate(II) e. tetraamminedichloroplatinum(IV) tetrachloroplatinate(II)

The complex ion Ru(phen)3 21 has been used as a probe for the structure of DNA. (Phen is a bidentate ligand.) a. What type of isomerism is found in Ru(phen)3 21? b. Ru(phen)3 21 is diamagnetic (as are all complex ions of Ru21). Draw the crystal field diagram for the d orbitals in this complex ion. Phen 5 1,10-phenanthroline 5 N N

Carbon monoxide is toxic because it binds more strongly to iron in hemoglobin (Hb) than does O2. Consider the following reactions and approximate standard free energy changes: Hb 1 O2 h HbO2 DG 5 270 kJ Hb 1 CO h HbCO DG 5 280 kJ Using these data, estimate the equilibrium constant value at 258C for the following reaction: HbO2 1 COmHbCO 1 O2

For the process Co1NH32 5Cl21 1 Cl2 h Co1NH32 4Cl2 1 1 NH3 what would be the expected ratio of cis to trans isomers in the product?

In which of the following is(are) the electron configuration(s) correct for the species indicated? a. Cu [Ar]4s2 3d9 b. Fe31 [Ar]3d5 c. Co [Ar]4s2 3d7 d. La [Ar]6s2 4f 1 e. Pt21 [Xe]4f 145d8

Which of the following molecules exhibit(s) optical isomerism? a. cis-Pt(NH3)2Cl2 b. trans-Ni(en)2Br2 (en is ethylenediamine)c. cis-Ni(en)2Br2 (en is ethylenediamine) d. 2 Co F Br Cl I

Which of the following ions is(are) expected to form colored octahedral aqueous complex ions? a. Zn21 b. Cu21 c. Mn31 d. Ti4

The following table indicates the number of unpaired electrons in the crystal field diagrams for some complexes. Complete the table by classifying each species as weak field, strong field, or insufficient information. Species Unpaired Electrons Classification Fe(CNS)6 42 0 ___________________ CoCl4 22 3 ___________________ Fe(H2O)6 31 5 ___________________ Fe(CN)6 42

for the complex given? a. Zn(NH3)4 21 (tetrahedral) b. Mn(CN)6 32 (strong field) c. Ni(CN)4 22 (square planar, diamagnetic)

Which of the following statement(s) is(are) true? a. The coordination number of a metal ion in an octahedral complex ion is 8. b. All tetrahedral complex ions are low-spin. c. The formula for triaquatriamminechromium(III) sulfate is [Cr(H2O)3(NH3)3]2(SO4)3. d. The electron configuration of Hf 21 is [Xe]4f 126s2 . e. Hemoglobin contains Fe31.

Consider the following complex ion, where A and B represent ligands. B B A B A B Ni2+ The complex is known to be diamagnetic. Do A and B produce very similar or very different crystal fields? Explain.

Consider the pseudo-octahedral complex ion of Cr31, where A and B represent ligands. B B B B A A Cr3+ Ligand A produces a stronger crystal field than ligand B. Draw an appropriate crystal field diagram for this complex ion (assume the A ligands are on the z-axis).

Consider the following data: Co31 1 e2 h Co21 % 5 1.82 V Co21 1 3en h Co1en2 3 21 K 5 1.5 3 1012 Co31 1 3en h Co1en2 3 31 K 5 2.0 3 1047 where en 5 ethylenediamine. a. Calculate % for the half-reaction Co1en2 3 31 1 e2 h Co1en2 3 21 b. Based on your answer to part a, which is the stronger oxidizing agent, Co31 or Co(en)3 31? c. Use the crystal field model to rationalize the result in part b.

Henry Taube, 1983 Nobel Prize winner in chemistry, has studied the mechanisms of the oxidationreduction reactions of transition metal complexes. In one experiment he and his students studied the following reaction: Cr1H2O2 6 21 1aq2 1 Co1NH32 5Cl21 1aq2 h Cr1III2 complexes 1 Co1II2 complexes Chromium(III) and cobalt(III) complexes are substitutionally inert (no exchange of ligands) under conditions of the experiment. Chromium(II) and cobalt(II) complexes can exchange ligands very rapidly. One of the products of the reaction is Cr(H2O)5Cl21. Is this consistent with the reaction proceeding through formation of 1H2O2 5CriCliCo1NH32 5 as an intermediate? Explain.

Chelating ligands often form more stable complex ions than the corresponding monodentate ligands with the same donor atoms. For example, Ni21 1aq2 1 6NH3 1aq2mNi1NH32 6 21 1aq2 K 5 3.2 3 108 Ni21 1aq2 1 3en1aq2mNi1en2 3 21 1aq2 K 5 1.6 3 1018 Ni21 1aq2 1 penten1aq2mNi1penten2 21 1aq2 K 5 2.0 3 1019 where en is ethylenediamine and penten is N CH2 2 NCH NH2CH2CH2 CH2CH2NH2 NH2CH2CH2 CH2CH2NH2 This increased stability is called the chelate effect. Based on bond energies, would you expect the enthalpy changes for the above reactions to be very different? What is the order (from least favorable to most favorable) of the entropy changes for the above reactions? How do the values of the formation constants correlate with DS8? How can this be used to explain the chelate effect?

Qualitatively draw the crystal field splitting of the d orbitals in a trigonal planar complex ion. (Let the z axis be perpendicular to the plane of the complex.)

Qualitatively draw the crystal field splitting for a trigonal bipyramidal complex ion. (Let the z axis be perpendicular to the trigonal plane.)

Sketch a d-orbital energy diagram for the following. a. a linear complex ion with ligands on the x axis b. a linear complex ion with ligands on the y axis

Sketch and explain the most likely crystal field diagram for the following complex ion: Ni CN 2 CN NC NC NH3 NH3 Note: The CN2 ligand produces a much stronger crystal field than NH3. Assume the NH3 ligands lie on the z axis.

The ferrate ion, FeO4 22, is such a powerful oxidizing agent that in acidic solution, aqueous ammonia is reduced to elemental nitrogen along with the formation of the iron(III) ion. a. What is the oxidation state of iron in FeO4 22, and what is the electron configuration of iron in this polyatomic ion? b. If 25.0 mL of a 0.243 M FeO4 22 solution is allowed to react with 55.0 mL of 1.45 M aqueous ammonia, what volume of nitrogen gas can form at 258C and 1.50 atm?

Ammonia and potassium iodide solutions are added to an aqueous solution of Cr(NO3)3. A solid is isolated (compound A), and the following data are collected: i. When 0.105 g of compound A was strongly heated in excess O2, 0.0203 g CrO3 was formed. ii. In a second experiment it took 32.93 mL of 0.100 M HCl to titrate completely the NH3 present in 0.341 g compound A. iii. Compound A was found to contain 73.53% iodine by mass. iv. The freezing point of water was lowered by 0.648C when 0.601 g compound A was dissolved in 10.00 g H2O (Kf 5 1.868C ? kg/mol).What is the formula of the compound? What is the structure of the complex ion present? (Hints: Cr31 is expected to be sixcoordinate, with NH3 and possibly I2 as ligands. The I2 ions will be the counterions if needed.

a. In the absorption spectrum of the complex ion Cr(NCS)6 32, there is a band corresponding to the absorption of a photon of light with an energy of 1.75 3 104 cm21 . Given 1 cm21 5 1.986 3 10223 J, what is the wavelength of this photon? b. The CriNiC bond angle in Cr(NCS)6 32 is predicted to be 1808. What is the hybridization of the N atom in the NCS2 ligand when a Lewis acidbase reaction occurs between Cr31 and NCS2 that would give a 1808 CriNiC bond angle? Cr(NCS)6 32 undergoes substitution by ethylenediamine (en) according to the equation Cr1NCS2 6 32 1 2en h Cr1NCS2 2 1en2 2 1 1 4NCS2 Does Cr(NCS)2(en)2 1 exhibit geometric isomerism? Does Cr(NCS)2(en)2 1 exhibit optical isomerism?

There are three salts that contain complex ions of chromium and have the molecular formula CrCl3 ? 6H2O. Treating 0.27 g of the first salt with a strong dehydrating agent resulted in a mass loss of 0.036 g. Treating 270 mg of the second salt with the same dehydrating agent resulted in a mass loss of 18 mg. The third salt did not lose any mass when treated with the same dehydrating agent. Addition of excess aqueous silver nitrate to 100.0-mL portions of 0.100 M solutions of each salt resulted in the formation of different masses of silver chloride; one solution yielded 1430 mg AgCl; another, 2870 mg AgCl; the third, 4300 mg AgCl. Two of the salts are green and one is violet. Suggest probable structural formulas for these salts, defending your answer on the basis of the preceding observations. State which salt is most likely to be violet. Would a study of the magnetic properties of the salts be helpful in determining the structural formulas? Explain.