Ch.23 - Transition Metals and Coordination Chemistry
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- Draw the structure for Pt (en) Cl₂ and use it to answer the following questions: a. What is the coordination number for platinum in this complex? b. What is the coordination geometry? c. What is the oxidation state of the platinum? d. How many unpaired electrons are there? [Find more in Sections 23.2 and 23.6.]
Problem 2
Problem 4
Four-coordinate metals can have either a tetrahedral or a square-planar geometry; both possibilities are shown here for [PtCl2(NH3)2].
a. What is the name of this molecule?
b. Would the tetrahedral molecule have a geometric isomer?
c. Would the tetrahedral molecule be diamagnetic or paramagnetic?
d. Would the square-planar molecule have a geometric isomer?
Problem 8
Which of these crystal-field splitting diagrams represents:
a. a weak-field octahedral complex of Fe³⁺ ,
b. a strong-field octahedral complex of Fe³⁺
c. a tetrahedral complex of Fe³⁺
d. a tetrahedral complex of Ni²⁺ (The diagrams do not indicate the relative magnitudes of ∆. ) [Find more in Section 23.6.]
Problem 9
In the linear crystal-field shown here, the negative charges are on the z-axis. Using Figure 23.28 as a guide, predict which of the following choices most accurately describes the splitting of the d orbitals in a linear crystal-field? [Find more in Section 23.6.]
- Complete the exercises below. Which periodic trend is partially responsible for the observation that the maximum oxidation state of the transition-metal elements peaks near groups 7B and 8B? a. The number of valence electrons reaches a maximum at group 8B. b. The effective nuclear charge increases on moving right across each period. c. The radii of the transition-metal elements reach a minimum for group 8B, and as the size of the atoms decreases it becomes easier to remove electrons.
Problem 12
- Among the period 4 transition metals (Sc–Zn), which elements do not form ions with partially filled 3d orbitals?
Problem 14
Problem 15b
Write out the ground-state electron configurations of b. Ru²⁺
Problem 15c
Write out the ground-state electron configurations of c. Au³⁺ ,
- Complete the exercises below. How many electrons are in the valence d orbitals in these transition-metal ions? a. Co³⁺, b. Cu⁺, c. Cd²⁺, d. Os³⁺.
Problem 16
Problem 17
Which type of substance is attracted by a magnetic field, a diamagnetic substance or a paramagnetic substance?
- Which type of magnetic material cannot be used to make permanent magnets: a ferromagnetic substance, an antiferromagnetic substance, or a ferrimagnetic substance?
Problem 18
- Complete the exercises below. a. Using Werner’s definition of valence, which property is the same as oxidation number, primary valence or secondary valence? b. What term do we normally use for the other type of valence? c. Why can NH₃ serve as a ligand but BH₃ cannot?
Problem 21
- Complete the exercises below. Which species are more likely to act as ligands? a. Positively charged ions or negatively charged ions? b. Neutral molecules that are polar or those that are nonpolar?
Problem 22
- Complete the exercises below. A complex is written as NiBr₂ • 6NH₃. a. What is the oxidation state of the Ni atom in this complex? b. What is the likely coordination number for the complex? c. If the complex is treated with excess AgNO₃ (aq), how many moles of AgBr will precipitate per mole of complex?
Problem 23
- Complete the exercises below. Crystals of hydrated chromium(III) chloride are green, have an empirical formula of CrCl₃ • 6H₂O, and are highly soluble. a. Write the complex ion that exists in this compound. b. If the complex is treated with excess AgNO₃ (aq), how many moles of AgCl will precipitate per mole of CrCl₃ • 6H₂O dissolved in solution? c. Crystals of anhydrous chromium(III) chloride are violet and insoluble in aqueous solution. The coordination geometry of chromium in these crystals is octahedral, as is almost always the case for Cr³⁺. How can this be the case if the ratio of Cr to Cl is not 1:6?
Problem 24
- Complete the exercises below. Indicate the coordination number and the oxidation number of the metal for each of the following complexes: a. Na₂ [CdCl₄] b. K₂ [MoOCl₄] c. [Co(NH₃)₄ Cl₂] Cl
Problem 25
- Complete the exercises below. Indicate the coordination number and the oxidation number of the metal for each of the following complexes: e. NH₄[Cr(NH₃)₂(NCS)₄]
Problem 26
- Complete the exercises below. For each of the following molecules or polyatomic ions, draw the Lewis structure and indicate if it can act as a monodentate ligand, a bidentate ligand, or is unlikely to act as a ligand at all: a. ethylamine, CH₃CH₂NH₂, b. trimethylphosphine, P(CH₃)₃.
Problem 27
- Complete the exercises below. Polydentate ligands can vary in the number of coordination positions they occupy. In each of the following, identify the polydentate ligand present and indicate the probable number of coordination positions it occupies: a. [Co(NH₃)₄ (o-phen)] Cl₃.
Problem 29
- Complete the exercises below. For each of the following pairs, identify the molecule or ion that is more likely to act as a ligand in a metal complex: a. acetonitrile (CH₃CN) or ammonium (NH₄⁺),
Problem 31
- Complete the exercises below. Write the formula for each of the following compounds, being sure to use brackets to indicate the coordination sphere: e. bis(ethylenediamine)zinc(II) tetraiodomercurate(II).
Problem 35
- Complete the exercises below. Write the formula for each of the following compounds, being sure to use brackets to indicate the coordination sphere: e.g., tris(ethylenediamine)rhodium(III), tris(oxalato)cobaltate(III).
Problem 36
- Complete the exercises below. Write the names of the following compounds, using the standard nomenclature rules for coordination complexes: d. [Pt(H₂O)₄(C₂O₄)]Br₂
Problem 37
- Complete the exercises below. Write names for the following coordination compounds: d. [Ir(NH₃)₄(H₂O)₂](NO₃)₃
Problem 38
- Complete the exercises below. Consider the following three complexes: (Complex 1) [Co(NH₃)₄Br₂]Cl (Complex 2) [Pd(NH₃)₂(ONO)₂] (Complex 3) [V(en)₂Cl₂]⁺. Which of the three complexes can have: a. geometric isomers, b. linkage isomers, c. optical isomers, d. coordination-sphere isomers?
Problem 39
- Complete the exercises below. A four-coordinate complex MA₂B₂ is prepared and found to have two different isomers. Is it possible to determine from this information whether the complex is square planar or tetrahedral? If so, which is it?
Problem 41
- Complete the exercises below. Consider an octahedral complex MA₃B₃. How many geometric isomers are expected for this compound? Will any of the isomers be optically active? If so, which ones?
Problem 42
- Complete the exercises below. Determine if each of the following complexes exhibits geometric isomerism. If geometric isomers exist, determine how many there are. c. octahedral [Fe(o-phen)₂ Cl₂]⁺.
Problem 43
- Complete the exercises below. Determine if each of the following complexes exhibits geometric isomerism. If geometric isomers exist, determine how many there are. c. Square-planar [Pd(en)(CN)₂].
Problem 44
- Complete the exercises below. Determine if each of the following metal complexes is chiral and therefore has an optical isomer: b. octahedral trans-[Ru(bipy)₂Cl₂].
Problem 45