Download Review Questions -- Chapter 23 1. For each of the following metal

Review Questions -- Chapter 23
1. For each of the following metal complexes, give the oxidation state of the metal and
the complete, systematic name of the compound or ion.
(a)
Na[Fe(CN)3(NH3)3]
(b)
[Cr(en)2Br2]2SO4
(c)
[Rh(NH3)5CN]Cl2.
2. Draw clear, 3-dimensional structures of all of the isomers, geometric and/or optical, of
the following complex. Points will be deducted if the same structure is drawn more than
once.
Co(en)2(CN)Br
3. For each of the following complexes, A and B, sketch a properly-labeled d-orbital
splitting diagram. Then answer the questions below in a manner consistent with your
diagrams.
A: [Mn(H2O)6]2+
B: [Mn(NO2)6]4-
(a) How many unpaired electrons does complex A have?
(b) Which complex, A or B, will absorb light of longer wavelength?
4. a. An octahedral manganese (III) complex has a spin of 2 (i.e., 4 × ½). Sketch the
energy level diagram for the d orbitals in this complex.
b.
Which of the following ligands is most likely to be attached to the Mn ion in this
complex. Explain briefly.
Cl-
CN-
.
5. For the complex [Pt(NH2Me)(NH3)2Cl]+, draw the structures for all the possible isomers
of the cation. [Note: Me represents a methyl or CH3 group.]
6. Draw the structure for the geometric isomers of Co(en)NH3Cl3.
en = H2NCH2CH2NH2
7. Give the structural formula for each of the following. .
a. tetrakis(trimethylamine)palladium (II) nitrate
page 2
b.
potassium hexacyanoferrate (II)
8. Predict the spin state (high or low) and the number of unpaired electrons in the following
complexes. Show how you arrived at your answers.
[CoF6]-3
[Fe(CN)6]-3
[Ir(NH3)6]+3
page 3
Answers
1. For each of the following metal complexes, give the oxidation state of the metal and
the complete, systematic name of the compound or ion.
(a)
Na[Fe(CN)3(NH3)3]
Name:
(b)
Charge on Fe is 2+
sodium triamminetricyanoferrate(II)
[Cr(en)2Br2]2SO4
Name:
Charge on Cr is 3+
dibromobis(ethylenediamine)chromium(III) sulfate
(c) [Rh(NH3)5CN]Cl2.
Name:
pentamminecyanorhodium(III) chloride
2. Draw clear, 3-dimensional structures of all of the isomers, geometric and/or optical, of
the following complex. Points will be deducted if the same structure is drawn more than
once.
Co(en)2(CN)Br
Br
N
N
Co
N
N
N
N
CN
N
N
Co
N
Br
N
N
CN
CN
trans
Co
Br
N
enantiomers of the
cis isomer
3. For each of the following complexes, A and B, sketch a properly-labeled d-orbital
splitting diagram. Then answer the questions below in a manner consistent with your
diagrams.
A: [Mn(H2O)6]2+
B: [Mn(NO2)6]4-
See lecture notes and/or textbook for the d-orbital splitting diagrams.
complexes are Mn2+ which is a d5 configuration.
Both
Complex B will have a larger splitting energy (∆) than A because CN- is a strong
field ligand whereas H2O is a weak field ligand.
page 4
Consequently, A will have 5 unpaired electrons and B will have 1.
Complex A, which has the smaller ∆ value, will absorb light of lower energy,
lower frequency, and hence longer wavelength.
4. a. An octahedral manganese (III) complex has a spin of 2 (i.e., 4 × ½). Sketch the
energy level diagram for the d orbitals in this complex.
eg
dz2
dx2-y2
∆
t2g
dxy
b.
dxz
dyz
Which of the following ligands is most likely to be attached to the Mn ion in this
complex. Explain briefly.
ClCN-
Chloride (Cl-) is most likely to be the ligand because it is the weakest field ligand
according to the spectrochemical series so ∆ will be the smallest resulting in more
unpaired electrons
5. For the complex [Pt(NH2Me)(NH3)2Cl]+, draw the structures for all the possible isomers
of the cation. [Note: Me represents a methyl or CH3 group.]
NH3
Cl
Pt
NH2Me
+
NH3
NH3
Cl
trans
Pt
NH3
NH2Me
cis
6. Draw the structure of the geometric isomers of Co(en)NH3Cl3.
en = H2NCH2CH2NH2
Cl
Cl
N
N
Co
NH3
Cl
N
N
Co
Cl
7. Give the structural formula for each of the following. .
a. tetrakis(trimethylamine)palladium (II) nitrate
NH3
Cl
Cl
+
page 5
{Pd[N(CH3]3)4}(NO3)2
b.
potassium hexacyanoferrate (II)
K4[Fe(CN)6]
8. Predict the spin state (high or low) and the number of unpaired electrons in the following
complexes. Show how you arrived at your answers.
[CoF6]-3
[Fe(CN)6]-3
eg
dz2
dz2
dx2-y2
dz2
dx2-y2
dyz
high spin (∆ is small)
4 unpaired electrons
dx2-y2
∆
t2g
dxz
eg
eg
∆
dxy
[Ir(NH3)6]+3
∆
t2g
t2g
dxy
dxz
dyz
low spin (∆ is large)
1 unpaired electron
dxy
dxz
dyz
low spin (∆ is large)
0 unpaired electrons