Chapter 22

What characteristics of the transition elements set them apart from the main- group elements?

According to the building-up principle, what is the electron configuration of the ground state of the technetium atom (atomic number 43)?

The highest melting point for metals in the fifth period occurs for molybdenum. Explain why this is expected.

Iron, cobalt, and nickel are similar in properties and are sometimes studied together as the "iron triad." For example, each is a fairly active metal that reacts with acids to give hydrogen and the \(+2\) ions. In addition to the \(+2\) ions, the \(+3\) ions of the metals also figure prominently in the chemistries of the elements. Explain why these elements are similar.

Palladium and platinum are very similar to one another. Both are unreactive toward most acids. However, nickel, which is in the same column of the periodic table, is an active metal. Explain why this difference exists.

Write balanced equations for the reactions of \(\mathrm{Cr}\) and \(\mathrm{Cu}\) metals with \(\mathrm{HCl}(a q)\). If no reaction occurs, write \(N R\)

Describe the structure of copper(II) sulfate pentahydrate. What color change occurs when the salt is heated? What causes the color change?

Copper(II) ion in basic solution is reduced by formaldehyde, HCHO, to copper(I) oxide. Formaldehyde is oxidized to formate ion, \(\mathrm{HCOO}^{-}\). Write the balanced equation for this reaction.

Define the terms complex ion, ligand, and coordination number. Use an example to illustrate the use of these terms.

Define the term bidentate ligand. Give two examples.

Define each of the following and give an example of each: (a) ionization isomerism, (b) hydrate isomerism, (c) coordination isomerism, (d) linkage isomerism.

Define the terms geometric isomerism and optical isomerism and give an example of each.

Explain the difference in behavior of \(d\) and \(l\) isomers with respect to polarized light.

What is a racemic mixture? Describe one method of resolving a racemic mixture.

Explain why \(d\) orbitals of a transition-metal atom may have different energies in the octahedral field of six negative charges. Describe how each of the \(d\) orbitals is affected by the octahedral field.

(a) Use crystal field theory to describe a high-spin octahedral complex of \(\mathrm{Fe}^{2+}\). (b) Do the same for a low-spin complex.

What is meant by the term crystal field splitting? How is it determined experimentally?

What is the spectrochemical series? Use the ligands \(\mathrm{CN}^{-}, \mathrm{H}_{2} \mathrm{O}, \mathrm{Cl}^{-}\), and \(\mathrm{NH}_{3}\) to illustrate the term. Then arrange them in order, describing the meaning of this order.

What is the spectrochemical series? Use the ligands \(\mathrm{CN}^{-}, \mathrm{H}_{2} \mathrm{O}, \mathrm{Cl}^{-}\), and \(\mathrm{NH}_{3}\) to illustrate the term. Then arrange them in order, describing the meaning of this order.

What is the spectrochemical series? Use the ligands \(\mathrm{CN}^{-}, \mathrm{H}_{2} \mathrm{O}, \mathrm{Cl}^{-}\), and \(\mathrm{NH}_{3}\) to illustrate the term. Then arrange them in order, describing the meaning of this order.

What is the coordination number of cobalt in the complex \(\left[\mathrm{Co}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right] \mathrm{ClO}_{4} ?\) a. 2 b. 3 c. 4 d. 5 e. 6

Which of the following is most likely a tetrahedral complex? a. \(\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right]\) b. \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}_{3}\right]\) C. \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}\) d. \(\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{SO}_{4}\) e. \(\left[\mathrm{Co}(\mathrm{en})_{2}\left(\mathrm{H}_{2} \mathrm{O}\right) \mathrm{Cl}\right]^{2+}\)

What is the correct name for the coordination compound \(\left[\mathrm{Cr}(\mathrm{en})_{2}(\mathrm{CN})_{2}\right] \mathrm{Cl} ?\) a. chromium(III) (diethylenediamine)biscyano chloride b. dicyanobis(ethylenediamine)chromium(III) chloride c. dicyanobis(ethylenediamine)chromium(III) dichloride d. bis(ethylenediamine)dicyanochromium(III) chloride e. bis(ethylenediamine)dicyanochromium(III) dichloride

What is the number of unpaired electrons in the low-spin complex \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}\) a. 0 b. 1 c. 2 d. 3 e. 4

A cobalt complex whose composition corresponded to the formula \(\mathrm{Co}\left(\mathrm{NO}_{2}\right)_{2} \mathrm{Cl} \cdot 4 \mathrm{NH}_{3}\) gave an electrical conductance equivalent to two ions per formula unit. Excess silver nitrate solution immediately precipitates \(1 \mathrm{~mol} \mathrm{AgCl}\) per formula unit. Write a structural formula consistent with these results.

Describe step by step how the name potassium hexacyanoferrate(II) leads to the structural formula \(\mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\)

Compounds \(A\) and \(B\) are known to be stereoisomers of one another. Compound A has a violet color; compound B has a green color. Are they geometric or optical isomers?

A complex has a composition corresponding to the formula \(\mathrm{CoBr}_{2} \mathrm{Cl} \cdot 4 \mathrm{NH}_{3} .\) What is the structural formula if conductance measurements show two ions per formula unit? Silver nitrate solution gives an immediate precipitate of \(\mathrm{AgCl}\) but no AgBr. Write the structural formula of an isomer.

Find the oxidation numbers of the transition metal in each of the following compounds: a. \(\mathrm{FeCO}_{3}\) b. \(\mathrm{MnO}_{2}\) c. \(\mathrm{CuCl}_{2}\) d. \(\mathrm{CrO}_{2} \mathrm{Cl}_{2}\)

Find the oxidation numbers of the transition metal in each of the following compounds: a. \(\mathrm{CoSO}_{4}\) b. \(\mathrm{Ta}_{2} \mathrm{O}_{5}\) c. \(\mathrm{Cu}_{2}(\mathrm{OH})_{3} \mathrm{Cl}\)

Write the balanced equation for the reaction of iron(II) ion with nitrate ion in acidic solution. Nitrate ion is reduced to NO.

Give the coordination number of the transition-metal atom in each of the following complexes. a. \(\left[\mathrm{Au}(\mathrm{CN})_{4}\right]\) b. \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\right] \mathrm{Cl}_{3}\) c. \(\left[\mathrm{Au}(\mathrm{en})_{2}\right] \mathrm{Cl}_{3}\) d. \(\left[\mathrm{Cr}(\mathrm{en})_{2}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)\right]^{+}\)

Give the coordination number of the transition element in each of the following complexes. a. \(\left[\mathrm{Ni}\left(\mathrm{NH}_{3}\right)_{6}\right]\left(\mathrm{ClO}_{3}\right)_{2}\) b. \(\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{SO}_{4}\) c. \(\left[\mathrm{Cr}(\mathrm{en})_{3}\right] \mathrm{Cl}_{3}\) d. \(\mathrm{K}_{2}\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]\)

Determine the oxidation number of the transition element in each of the following complexes. a. \(\mathrm{K}_{2}\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]\) b. \(\left[\mathrm{Mo}(\mathrm{en})_{3}\right]^{3+}\) c. \(\left[\mathrm{Cr}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3-}\) d. \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5}\left(\mathrm{NO}_{2}\right)\right] \mathrm{Cl}_{2}\)

For each of the following complexes, determine the oxidation state of the transition-metal atom. a. \(\left[\mathrm{CoCl}(\mathrm{en})_{2}\left(\mathrm{NO}_{2}\right)\right] \mathrm{NO}_{2}\) b. \(\left[\mathrm{PtCl}_{4}\right]^{2-}\) c. \(\mathrm{K}_{3}\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]\) d. \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5}(\mathrm{OH})\right]^{2+}\)

Consider the complex ion \(\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)\right]^{-}\). a. What is the oxidation state of the metal atom? b. Give the formula and name of each ligand in the ion. C. What is the coordination number of the metal atom? d. What would be the charge on the complex if all ligands were chloride ions?

Consider the complex ion \(\left[\mathrm{Mn}\left(\mathrm{NH}_{3}\right)_{2}\left(\mathrm{H}_{2} \mathrm{O}\right)_{3}(\mathrm{OH})\right]^{2+}\). a. What is the oxidation state of the metal atom? b. Give the formula and name of each ligand in the ion. c. What is the coordination number of the metal atom? d. What would be the charge on the complex if all ligands were chloride ions?

Write the IUPAC name for each of the following coordination compounds. a. \(\mathrm{K}_{3}\left[\mathrm{FeF}_{6}\right]\) b. \(\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{2}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\right]^{2+}\) c. \(\left(\mathrm{NH}_{4}\right)_{2}\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right) \mathrm{F}_{5}\right]\) d. \(\left[\mathrm{Ag}(\mathrm{CN})_{2}\right]^{-}\)

Name the following complexes, using IUPAC rules. a. \(\mathrm{K}_{4}\left[\mathrm{Mo}(\mathrm{CN})_{8}\right]\) b. \(\left[\mathrm{CrF}_{6}\right]^{3-}\) c. \(\left[\mathrm{V}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{2-}\) d. \(\mathrm{K}_{2}\left[\mathrm{FeCl}_{4}\right]\)

Give the IUPAC name for each of the following. a. \(\left[\mathrm{Fe}(\mathrm{CO})_{5}\right]\) b. \(\left[\mathrm{Rh}(\mathrm{CN})_{2}(\mathrm{en})_{2}\right]^{+}\) c. \(\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{SO}_{4}\right] \mathrm{Cl}\) d. \(\left[\mathrm{MnO}_{4}\right]^{-}\)

Give the IUPAC name for each of the following. a. \(\left[\mathrm{W}(\mathrm{CO})_{8}\right]\) b. \(\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}(\mathrm{en})_{2}\right]\left(\mathrm{SO}_{4}\right)_{3}\) c. \(\mathrm{K}\left[\mathrm{Mo}(\mathrm{CN})_{8}\right]\) d. \(\left[\mathrm{CrO}_{4}\right]^{2-}\)

Write the structural formula for each of the following compounds. a. potassium hexacyanomanganate(III) b. sodium tetracyanozincate(II) c. tetraamminedichlorocobalt(III) nitrate d. hexaamminechromium(III) tetrachlorocuprate(II)

Give the structural formula for each of the following complexes. a. diaquadicyanocopper(II) b. potassium hexachloroplatinate(IV) c. tetraamminenickel(II) perchlorate d. tetraammineplatinum(II) tetrachlorocuprate(II)

Draw cis-trans structures of any of the following square planar or octahedral complexes that exhibit geometric isomerism. Label the drawings cis or trans. a. \(\left[\mathrm{Pd}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right]\) b. \(\left[\mathrm{Pd}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}\right]^{+}\) c. \(\left[\mathrm{Pd}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}\) d. \(\left[\mathrm{Ru}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Br}_{2}\right]^{+}\)

If any of the following octahedral complexes display geometric isomerism, draw the structures and label them cis or trans. a. \(\left[\mathrm{Co}\left(\mathrm{NO}_{2}\right)_{4}\left(\mathrm{NH}_{3}\right)_{2}\right]^{-}\) b. \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5}\left(\mathrm{NO}_{2}\right)\right]^{2+}\) c. \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}\) d. \(\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right]^{2+}\)

Determine whether there are optical isomers of any of the following. If so, sketch the isomers. a. cis-[Co(NH \(\left.\left._{3}\right)_{2}(\mathrm{en})_{2}\right]^{3+}\) b. trans- \(\left[\mathrm{IrCl}_{2}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{2}\right]^{3-}\)

Using crystal field theory, sketch the energy-level diagram for the \(d\) orbitals in an octahedral field; then fill in the electrons for the metal ion in each of the following complexes. How many unpaired electrons are there in each case? a. \(\left[\mathrm{V}(\mathrm{CN})_{6}\right]^{3-}\) b. \(\left[\mathrm{Co}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{4-}\) (high-spin) C. \(\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{3-}\) (low-spin)

Using crystal field theory, sketch the energy-level diagram for the \(d\) orbitals in an octahedral field; then fill in the electrons for the metal ion in each of the following complexes. How many unpaired electrons are there in each case? a. \(\left[\mathrm{ZrCl}_{6}\right]^{4-}\) b. \(\left[\mathrm{OsCl}_{6}\right]^{2-}\) (low-spin) c. \(\left[\mathrm{MnCl}_{6}\right]^{4-}\) (high-spin)

Obtain the distribution of \(d\) electrons in the complex ions listed below, using crystal field theory. Each ion is either tetrahedral or square planar. On the basis of the number of unpaired electrons (given in parentheses), decide the correct geometry. a. \(\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2}\left(\mathrm{NO}_{2}\right)_{2}\right]^{2+}\) b. \(\left[\mathrm{MnCl}_{4}\right]^{2-}\) c. \(\left[\mathrm{NiCl}_{4}\right]^{2-}(2)\) d. \(\left[\mathrm{AuF}_{4}\right]^{-}(0)\)

The \(\left[\mathrm{Co}(\mathrm{SCN})_{4}\right]^{2-}\) ion has a maximum absorption at \(530 \mathrm{~nm}\). What color do you expect for this ion?