Chapter 22

Identify, based on the position in the periodic table, the actinide elements among those in the following list: \(\mathrm{Co}, \mathrm{Cm}, \mathrm{Cd}, \mathrm{Ce}, \mathrm{CF}\).

Identify, based on the position in the periodic table, the actinide elements among those in the following list: Ta, Tc, Ti, Th, Tm.

Use the periodic table to identify the elements in the following list with unfilled \(4 d\) orbitals: rhodium, rhenium, ruthenium, rutherfordium, radium.

Use the periodic table to identify the elements in the following list with unfilled \(3 d\) orbitals: cadmium, cerium, cobalt, chromium, copper.

Identify the following as either chemical or physical properties of most transition metals: (a) can be oxidized. (b) have unpaired electrons (paramagnetism). (c) solids at \(25^{\circ} \mathrm{C}\) (d) metallic luster. (e) Compounds of the elements are often colored.

Iron is the most abundant transition element in nature. Identify common chemical and physical properties of this element.

Give the electron configuration for each of the following ions, and tell whether each is paramagnetic or diamagnetic. (a) \(\mathrm{Cr}^{3+}\) (c) \(\mathrm{Ni}^{2+}\) \((b) V^{2+}\) (d) \(\mathrm{Cu}^{+}\)

Identify two transition metal cations with each of the following electron configurations. (a) \([\mathrm{Ar}] 3 d^{6}\) (c) \([\mathrm{Ar}] 3 d^{5}\) (b) \(|\mathrm{Ar}| 3 d^{10}\) \((\mathrm{d})[\mathrm{Ar}] 3 d^{8}\)

Identify a cation of a first series transition metal that is isoelectronic with each of the following. (a) \(\mathrm{Fe}^{3+}\) (c) \(\mathrm{Fe}^{2+}\) \((b) Z n^{2+}\) \((d) C r^{3+}\)

Match up the isoelectronic ions on the following list. $$\mathrm{Cu}^{+} \mathrm{Mn}^{2+} \mathrm{Fe}^{2+} \mathrm{Co}^{3+} \mathrm{Fe}^{3+} \mathrm{Zn}^{2+} \mathrm{Ti}^{2+} \mathrm{V}^{3+}$$

The lanthanide contraction is given as an explanation for the fact that the \(6^{\text {th }}\) period transition metals have (a) lower densities than the \(5^{\text {th }}\) period transition elements. (b) atomic radii similar to the \(5^{\text {th }}\) period transition elements. (c) lower melting points than the \(5^{\text {th }}\) period transition elements.

Describe how the atomic radii of the transition metals change across a period and rationalize this change based on electronic structure.

What is the most common form that iron is found in the Earth's crust? (a) free metal (b) iron oxide (c) iron sulfide (d) iron silicate

In the reaction $$\begin{aligned} \operatorname{CuFeS}_{2}(s)+3 \operatorname{CuCl}_{2}(\text { aq }) & \longrightarrow \operatorname{CuCl}(s)+\operatorname{FeCl}_{2}(a q)+2 S(s) \end{aligned}$$ what element is oxidized and what element is reduced? (a) Sulfur is reduced, iron is oxidized. (b) Copper is reduced, sulfur is oxidized. (c) Sulfur is reduced, copper is oxidized. (d) This is not a redox reaction.

In the pyrometallurgy of iron, what two species serve as reducing agents?

Lime (CaO) is usually added to the blast furnace in the metallurgy of iron where it reacts with impurities present in iron ore. What of the following best describes its function? (a) \(\mathrm{CaO}\) acts as an oxidizing agent. (b) CaO acts as a reducing agent. (c) \(\mathrm{CaO}\) acts as an acid. (d) \(\mathrm{CaO}\) acts as a base.

One of the following nitrogen compounds or ions is not capable of serving as a ligand: \(\mathrm{NH}_{4}^{+}, \mathrm{NH}_{3}\) \(\mathrm{NH}_{2}^{-} .\) Identify this species, and explain your answer.

Give the oxidation number of the metal ion in each of the following compounds. (a) \(\left[\mathrm{Mn}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{SO}_{4}\) (c) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl}\) (b) \(\mathrm{K}_{3}\left[\mathrm{Co}(\mathrm{CN})_{6}\right]\) (d) \(\mathrm{Cr}(\mathrm{en})_{2} \mathrm{Cl}_{2}\)

Give the oxidation number of the metal ion in each of the following compounds. (a) \(\left[\mathrm{Mn}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{SO}_{4}\) (c) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl}\) (b) \(\mathrm{K}_{3}\left[\mathrm{Co}(\mathrm{CN})_{6}\right]\) (d) \(\mathrm{Cr}(\mathrm{en})_{2} \mathrm{Cl}_{2}\)

Give the formula of a complex constructed from one \(\mathrm{Ni}^{2+}\) ion, one ethylenediamine ligand, three ammonia molecules, and one w$$\left[\mathrm{Ni}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{3}\left(\mathrm{H}_{2} \mathrm{O}\right)\right]^{2+}$$ter molecule. Is the complex neutral or is it charged? If charged, give the charge.

Give the formula of a complex constructed from one \(\mathrm{Cr}^{3+}\) ion, two ethylenediamine ligands, and two ammonia molecules. Is the complex neutral or is it charged? If charged, give the charge.

Write formulas for the following ions or compounds. (a) dichlorobis(ethylenediamine)nickel(II) (b) potassium tetrachloroplatinate(II) (c) potassium dicyanocuprate(I) (d) tetraamminediaquairon(II)

Write formulas for the following ions or compounds. (a) diamminetriaquahydroxochromium(II) nitrate (b) hexaammineiron(III) nitrate (c) pentacarbonyliron(0) (where the ligand is CO) (d) ammonium tetrachlorocuprate(II)

Name the following ions or compounds. (a) \(\left[\mathrm{Ni}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{2}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\right]^{2-}\) (b) \(\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Br}_{2}\right]^{+}\) (c) \(\left[\mathrm{Co}(\mathrm{en})_{2}\left(\mathrm{NH}_{3}\right) \mathrm{Cl}\right]^{2+}\) (d) \(\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)\)

Give the name or formula for each ion or compound, as appropriate. (a) pentaaquahydroxoiron(III) ion (b) \(\mathrm{K}_{2}\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]\) (c) \(\mathrm{K}\left[\mathrm{Cr}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{2}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\right]\) (d) ammonium tetrachloroplatinate(II)

Give the name or formula for each ion or compound, as appropriate. (a) tetraaquadichlorochromium(III) chloride (b) \(\left|\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{SO}_{4}\right| \mathrm{Cl}\) (c) sodium tetrachlorocobaltate(II) (d) \(\left[\mathrm{Fe}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]^{3}\)

A coordination compound has the formula \(\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}(\mathrm{en}=\) ethylenediamine, \(\left.\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\right) .\) What types of isomerism (geometric isomerism, optical isomerism, structural isomerism) are possible with this formula? Identify all possible answers.

What types of isomerism (geometric isomerism, optical isomerism, structural isomerism) are possible in the compound diamminechlorothio-cyanatoplatinum (II)? Identify all possible answers.

In which of the following complexes are geometric isomers possible? If isomers are possible, draw their structures and label them as cis or trans, or as fac or mer. (a) \(\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4} \mathrm{Cl}_{2}\right]^{+}\) (c) \(\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right) \mathrm{Br}_{3}\right]^{-}\) (b) \(\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{F}_{3}\) \((\mathrm{d})\left[\mathrm{Co}(\mathrm{en})_{2}\left(\mathrm{NH}_{3}\right) \mathrm{Cl}\right]^{2+}\)

Four geometric isomers are possible for \(\left[\mathrm{Co (\mathrm{en})\left(\mathrm{NH}_{3}\right)_{2}\left(\mathrm{H}_{2} \mathrm{O}\right) \mathrm{Cl}\right]^{+} .\) Draw the structures of all four. (Two of the isomers are chiral, meaning that each has a non-superimposable mirror image.)

Which of the following statements about ligand field theory are correct? (a) Ligands donate an electron pair to a metal ion. (b) Each ligand donates an electron pair to the metal. (c) Coordination of the ligands to a metal causes splitting of the \(d\) electron energy levels. (d) Bonding of ligands to a metal results in paramagnetism.

In an octahedral complex, the \(d\) orbitals split into two groups. Which \(d\) orbitals are in the lower energy group? (Assume the ligands lie along the \(x\), \(y, \text { and } z \text { axes. })\)

In a square planar complex which \(d\) orbital is at lowest energy? Which \(d\) orbital is at highest energy? (Assume the ligands lie along the \(x\) and \(y\) axes.)

The following are high-spin complexes. Use the ligand field model to find the electron configuration of the central metal ion in each ion. Determine the number of unpaired electrons, if any, in each. (a) \(\mathrm{K}_{4}\left[\mathrm{FeF}_{6}\right]\) (c) \(\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) (b) \(\left|\mathrm{MnF}_{6}\right|^{4-}\) \(\left.(\mathrm{d})\left(\mathrm{NH}_{4}\right)_{3} | \mathrm{FeF}_{6}\right]\)

Determine the number of unpaired electrons in the following tetrahedral complexes. All tetrahedral complexes are high spin. (a) \(\left[\mathrm{FeCl}_{4}\right]^{2-}\) (c) \(\left[\mathrm{MnCl}_{4}\right]^{2}\) (b) \(\mathrm{Na}_{2}\left[\mathrm{CoCl}_{4}\right]\) \((\mathrm{d})\left(\mathrm{NH}_{4}\right)_{2}\left[\mathrm{ZnCl}_{4}\right]\)

Determine the number of unpaired electrons in the following tetrahedral complexes. All tetrahedral complexes are high spin. (a) \(\left[\mathrm{Zn}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4}\right]^{2+}\) (c) \(\mathrm{Mn}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\) (b) VOCI_ \((d)\left[C u(e n)_{2}\right]^{2+}\)

For the low-spin complex \(\left[\mathrm{Co}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right] \mathrm{ClO}_{4}\) identify the following: (a) the coordination number of cobalt (b) the coordination geometry for cobalt (c) the oxidation number of cobalt (d) the number of unpaired electrons (e) whether the complex is diamagnetic or paramagnetic

The anion \(\left[\mathrm{NiCl}_{4}\right]^{2-}\) is paramagnetic, but when \(\mathrm{CN}^{-}\) ions are added, the product, \(\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-},\) is diamagnetic. Explain this observation. \(\left[\mathrm{NiCl}_{4}\right]^{2-}(\mathrm{aq})+4 \mathrm{CN}^{-}(\mathrm{aq}) \longrightarrow\) paramagnetic \(\quad\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-}(\mathrm{aq})+4 \mathrm{Cl}^{-}(\mathrm{aq})\)

In water, the titanium(III) ion, \(\left[\mathrm{Ti}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+},\) has a broad absorption band centered at about \(500 \mathrm{nm}\) What color light is absorbed by the ion?

In water, the chromium(II) ion, \(\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) absorbs light with a wavelength of about \(700 \mathrm{nm}\). What color is the solution?

Describe an experiment that would determine whether nickel in \(\mathrm{K}_{2}\left[\mathrm{NiCl}_{4}\right]\) is square-planar or tetrahedral.

Which of the following high-spin complexes has the greatest number of unpaired electrons? (a) \(\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}\) \((c)\left[\operatorname{re}\left(H_{2} O\right)_{6}\right]^{2+}\) \((b)\left[\operatorname{Mn}\left(H_{2} O\right)_{6}\right]^{2+}\) \((d)\left[N i\left(H_{2} O\right)_{6}\right]^{2+}\)

How many unpaired electrons are expected for high-spin and low-spin complexes of \(\mathrm{Fe}^{2+} ?\)

Excess silver nitrate is added to a solution containing 1.0 mol of \(\left|\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right| \mathrm{Cl} .\) What amount of AgCl (in moles) will precipitate?

Which of the following complex ions is (are) square-planar? (a) \(\left[\mathrm{Ti}(\mathrm{CN})_{4}\right]^{2}\) (c) \(\left[\mathrm{Zn}(\mathrm{CN})_{4}\right]^{2}\) (b) \(\left.| \mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-}\) \((\mathrm{d})\left[\mathrm{Pt}(\mathrm{CN})_{4}\right]^{2-}\)

Which of the following complex ions containing the oxalate ion is (are) chiral? (a) \(\left[\mathrm{Fe}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right) \mathrm{Cl}_{4}\right]^{2-}\) (b) \(c i s-\left[\mathrm{Fe}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{2} \mathrm{Cl}_{2}\right]^{2}\) (c) trans - \(-\left[\mathrm{Fe}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{2} \mathrm{Cl}_{2}\right]^{2-}\)

How many geometric isomers are possible for the square-planar complex ion \(\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)(\mathrm{CN}) \mathrm{Cl}_{2}\right]^{-} ?\)

For a tetrahedral complex of a metal in the first transition series, which of the following statements concerning energies of the \(3 d\) orbitals is correct? (a) The five \(d\) orbitals have the same energy. (b) The \(d_{x^{2}-y^{2}}\) and \(d_{z^{2}}\) orbitals are higher in energy than the \(d_{x y} d_{y y}\) and \(d_{x y}\) orbitals. (c) The \(d_{x z} d_{y z}\) and \(d_{x y}\) orbitals are higher in energy than the \(d_{x^{2}-y^{2}}\) and \(d_{z^{2}}\) orbitals.

For the low-spin coordination compound \(\left[\mathrm{Fe}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl},\) identify the following. (a) the oxidation number of iron (b) the coordination number for iron (c) the coordination geometry for iron (d) the number of unpaired electrons per metal atonn (e) whether the complex is diamagnetic or paramagnetic (f) the number of geometric isomers

For the high-spin coordination compound \(\mathrm{Mn}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2},\) identify the following. (a) the oxidation number of manganese (b) the coordination number for manganese (c) the coordination geometry for manganese (d) the number of unpaired electrons per metal atom (e) whether the complex is diamagnetic or paramagnetic (f) the number of geometric isomers