Download Chapters 1-5 Practice Problems

KEY
Practice Problems: Transition Elements and Coordination
Chemistry
CHEM 1B
1. Complete the valence level orbital notation for the following monatomic ions.
a) Ag+
b) Co3+
4d
5s
c) Fe3+
3d
4s
3d
4s
d) Cr3+
3d
4s
2. For each of the following complexes, determine the number of ligands and the coordination number
and oxidation number of the central metal.
# Ligands
Coordination #
Oxidation #
[Mn(EDTA)]2–
1
6
+2
[Co(en)2(NH3)CN]2+
4
6
+3
Pt(NH3)2Cl2
4
4
+2
3. Give the ligand name for each of the following ligands. Donor atom(s) are written in bold. The
bottom three in the third column are common abbreviations rather than formulas.
aqua
H2O _________________
oxalato
C2O42– _________________
cyano
CN– _________________
fluoro
F– _________________
ammine
NH3 _________________
thiocyanato
SCN– _________________
Cl– _________________
chloro
NO2– _________________
nitro
NCS– _________________
isothiocyanato
bromo
Br– _________________
nitrito
ONO– _________________
ethylenediamine
en _________________
iodo
I– _________________
hydroxo
OH– _________________
glycinato
gly– _________________
carbonato
CO32– _________________
carbonyl
ethylenediaminetetraacetato
CO _________________
EDTA4– _________________
4. Circle the ligands above that would require the use of the bis-, tris-, or tetrakis- numeric prefixes in
the naming of the complex. Explain why below:
Bis-, tris-, tetrakis-, pentakis-, etc. are used with parentheses around the ligand name when the
name of the ligand already contains a common numeric prefix (mono-, di-, tri-, etc.), like in
ethylenediamine and ethylenediaminetetraacetate.
They are also used if the ligand is polydentate, which applies to all four of the circled ligands.
Note: Since EDTA4– is a hexadentate ligand, it is unlikely that more than one will complex the same metal center,
making the use of these prefixes less likely for EDTA4–.
5. Name the following complex cations, neutral complexes, and complex anions.
[Cr(H2O)5Cl]
2+
[Pt(en)2(SCN)2]2+
2+
[Co(NH3)5(NO2)]
–
ethylenediaminetetraacetatoferrate(III)
ion
________________________
pentaaquachlorochromium(III) ion
________________________
[Fe(EDTA)]
bis(ethylenediamine)dithiocyanatoplatinum(IV) ion
________________________
ion
[Co(CO3)3]3– tricarbonatocobaltate(III)
________________________
diamminebis(oxalato)chromate(III)
– ion
pentaamminenitrocobalt(III)
ion
________________________ [Cr(NH3)2(C2O4)2] ________________________
tris(ethylenediamine)cobalt(III) ion
[Co(en)3]3+ ________________________
ion
[Co(NCS)4]2– tetraisothiocyanatocobaltate(II)
________________________
tetracarbonylnickel(0)
Ni(CO)4 ________________________
ion
[Fe(CN)6]4– hexacyanoferrate(II)
________________________
6. Name the following coordination compounds.
tetraamminedibromocobalt(III)
pentaamminenitritocobalt(III) sulfate [Co(NH3)4Br2]Br bromide
[Co(NH3)5(ONO)]SO4 ________________________
________________________
diamminesilver(I) dicyanoargentate(I)
[Ag(NH3)2][Ag(CN)2] ________________________
tris(oxalato)ferrate(III)
K3[Fe(C2O4)3] potassium
________________________
7. Matching: Match the descriptions below with the letter of a type of isomer on the left. Each letter
can be used more than once or not at all.
A
_______
general category for isomers with different bonds
A = Structural Isomers
D
_______
general category for isomers with the same bonds
arranged in different locations
B = Coordination Isomers
F
_______
isomers with chiral centers
C = Linkage Isomers
E
_______
cis- and trans- isomers
D = Stereoisomers
F
_______
isomers that rotate plane polarized light
E = Geometric Isomers
C
_______
isomers that have functional groups bonded through
different atoms
F = Optical Isomers
_______
isomers that have the same atoms bonded, but
B
bonded in a different way
E
_______
isomers that occur as the result of rigid bonds
8. Draw condensed structures for 2-propanol, 2-butanol, and 2-butanone. Mark any chiral carbons with
an asterisk.
OH
CH3CHCH3
2-propanol
OH
CH3CHCH2CH3
*
2-butanol
O
CH3CCH2CH3
2-butanone
9. The crystal field splitting energy of a complex is 2.9 x 10 –19 J.
680 nm a) What wavelength of light (in nm) would be absorbed for this d-d electronic transition?
_______
red
_______
b) To what color of light does this wave length correspond?
green c) What color would a solution of this complex appear?
_______
hc

|Eelectron| = Ephoton =
2.9 x 10–19 J =
(6.626 x 10–34 J·s)(2.998 x 108 m/s)

 = 6.849913103 x 10–7 m
1 nm
= 680 nm
10–9 m
10. Determine the following for the complex ion: [Cu(en)3]2+
d9
a) What type of d-electron complex is it (for example: d0, d1, d2, etc.)? _______
b) Is the ligand a strong field ligand or a weak field ligand (circle one)?
c) Would you expect the complex to be high spin or low spin (circle one)?
d) On which piece of information, a) or b) (circle one), did you base your answer for Part c)?
3 2
sp d
e) What is the hybridization of the central metal? _______
f) Fill in the valence level orbital notation below, circle the electrons that come from the ligands.
____ ____ ____ ____ ____
____
____ ____ ____
____ ____ ____ ____ ____
3d
4s
4p
4d
11. Label each orbital with the appropriate
d-orbital designation (below the
orbital).
dyz
dxz
dx2 – y2
dxy
dz2
12. Label each orbital in the octahedral complex with the appropriate d-orbital designation (below the
orbital). For the complex [CoF6]3–:
a) Is o relatively large or small (circle one)?
>
b) How do the values of the splitting and the e pairing energies compare? Circle one: o = P
<
c) Is the complex high spin or low spin (circle one)?
–
d) Fill in the valence electrons from the metal in both the isolated ion and the complex.
dx2 – y2 dz2
dxy
d-orbitals in isolated atom/ion
dxz
o
dyz
d-orbitals in the complex
e) Fill in the valence level orbital notation below, circle the electrons that come from the ligands.
____ ____ ____ ____ ____
____
____ ____ ____
____ ____ ____ ____ ____
3d
4s
4p
4d
3 2
sp d
f) What is the hybridization of the orbitals on the central metal ion? ___________
g) Based on the orbital notation in Part e) above, would you expect the complex to be
paramagnetic or diamagnetic (circle one)?
13. For the complex [Co(CN)6]3–:
a) Is o relatively large or small (circle one)?
–
b) How do the values of the splitting and the e pairing energies compare? Circle one: o
c) Is the complex high spin or low spin (circle one)?
>
= P
<
d) Fill in the valence electrons from the metal in both the isolated ion and the complex.
o
d-orbitals in isolated atom/ion
d-orbitals in the complex
e) Fill in the valence level orbital notation below, circle the electrons that come from the ligands.
____ ____ ____ ____ ____
____
____ ____ ____
____ ____ ____ ____ ____
3d
4s
4p
4d
2
3
d sp
f) What is the hybridization of the orbitals on the central metal ion? ___________
g) Based on the orbital notation in Part e) above, would you expect the complex to be
paramagnetic or diamagnetic (circle one)?
14. For each of the following d-orbital splitting patterns, label each orbital with the appropriate dorbital designation (below the orbital), and fill in the missing information.
dx2 – y2
dxy
dxz
dyz
t
o
dxy
dx2 – y2 dz2
dz2
dxz dyz
Geometry:
 is generally:
Spin is generally:
Hybridization:
tetrahedral
_________________
square planar
_________________
large or small
large or small
high or low
high or low
3
dsp2
______
sp
______
15. Fill in the valence level orbital notation below for the complex: [Pt(NH 3)4]2+ (square planar)
____ ____ ____ ____ ____
____
____ ____ ____
5d
6s
6p
16. Fill in the valence level orbital notation below for the complex: [MnCl4]2– (tetrahedral)
____ ____ ____ ____ ____
____
____ ____ ____
3d
4s
4p