Chapter 10 problems:

A. Multiple choice exercises:

1. Which statement most correctly describes crystal field theory for a d block complex of unspecified geometry?

a. The theory considers covalent interactions between a metal centre and the surrounding ligands.

b. The theory considers electrostatic interactions between a metal ion and the surrounding ligands which are taken to be point charges.

c. The theory rationalizes the non-degeneracy of the metal d orbitals by considering the electrostatic repulsions between point charge ligands and electrons in the metal d orbitals.

d. The theory rationalizes why the metal d orbitals are split into two levels.

2. Which of the following correctly places the ligands in their order in the spectrochemical series?

a. Br– < Cl– < NH3 < H2O

b. I– < Br– < H2O < [OH]–

c. F– < Cl– < H2O < NH3

d. I– < Cl– < H2O < en

3. Which of the following correctly places the metal centers in order of increasing field strength?

  1. Mn(II) < Fe(III) < Rh(III)
  2. Co(III) < Co(II) < Rh(III)
  3. Pt(IV) < Pd(II) < Ni(II)
  4. Pd(II) < Ni(II) < Pt(IV)

4. Which of the following complex ions is tetrahedral?

  1. [PdCl4]2–
  2. [PtCl4]2–
  3. [NiCl4]2–
  4. [AuCl4]2–

5. Match up the correct formula and magnetic property. Which pair is correct?

  1. [Zn(H2O)6]2+; paramagnetic
  2. [Co(NH3)6]3+; diamagnetic
  3. [CoF6]3–; diamagnetic
  4. [V(H2O)6]2+; diamagnetic

B. Short essay problems:

1. Predict the correct hybridization for the metal ion in the following complexes, based on the concepts of the valence bond theory.

a. a diamagnetic d6 octahedral complex.

b. a paramagnetic d6 octahedral complex.

c. a diamagnetic d8 square planar complex.

d. a paramagnetic d5 tetrahedral complex.

e. a linear 2-coordinate d10 complex.

2. Use the concepts of crystal field theory to predict the d-orbital splitting in:

  1. octahedral complexes
  2. tetrahedral complexes
  3. trigonal bipyramidal complexes
  4. square planar complexes

3. Use the concepts of ligand field theory to construct the s-bonding scheme for:

  1. octahedral complexes (Oh)
  2. tetrahedral complexes (Td)
  3. square planar complexes (D4h)

4. Answer the following questions for all complexes below:

a. Write down the electronic configuration for the free ion.

b. Explain why each complex should have a high-spin or low-spin configuration.

c. Sketch the electronic distribution of the d electrons in the crystal field orbitals for the appropriate geometry (octahedral or tetrahedral).

d. Calculate the spin multiplicity for each.

  1. [Cr(H2O)6]3+
  2. [NiBr4]2-
  3. [Fe(CN)6]3-
  4. [Cu(H2O)6]2+
  5. [CoF6]3– 
  6. [IrF6]3-
  7. [Cr(H2O)6]2+
  8. [Rh(en)3]2+
  9. [Co(CO)4]–
  10. [Co(bpy)3]3+

5. Make up a spectrochemical series from the following ligands (i.e., arrange their relative field strength):

Cl–, NH3, CO, SCN-, NCS-, H2O, en, CN-.

6. Predict whether the following 4-coordinate complexes are likely to be square planar or tetrahedral:

  1. [NiCl4]2-
  2. [PtBr4]2–
  3. [Ni(CN)4]2-
  4. [Ni(CO)4]