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1.
Which electron transitions are responsible for the colours of transition metal compounds?
A.
Between d orbitals and s orbitals
B.
Among the attached ligands
C.
From the metal ion to the attached ligands
D.
Between d orbitals
(Total 1 mark)
2.
Ligands can form dative covalent bonds with metal ions to form complex ions. Which of the
following can act as a ligand?
I.
Cl–
II.
NH3
III.
H2O
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
(Total 1 mark)
3.
Which metal nitrate solution is coloured?
A.
Zn (NO3)2(aq)
B.
Ni (NO3)2(aq)
C.
Mg (NO3)2(aq)
D.
Sc (NO3)3(aq)
(Total 1 mark)
IB Questionbank Chemistry
1
4.
When concentrated hydrochloric acid is added to a solution containing hydrated copper(II) ions,
the colour of the solution changes from light blue to green. The equation for the reaction is:
[Cu(H2O)6]2+(aq) + 4Cl–(aq) → [CuCl4]2–(aq) + 6H2O(l)
(i)
Explain what the square brackets around the copper containing species represent.
......................................................................................................................................
......................................................................................................................................
(1)
(ii)
Explain why the [Cu(H2O)6]2+ ion is coloured and why the [CuCl4]2– ion has a different
colour.
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(2)
(Total 3 marks)
IB Questionbank Chemistry
2
5.
Which statements are correct for the complex ion [CuCl4]2–?
I.
The oxidation number of Cu in the complex ion is +2.
II.
The coordination number of the copper ion is 4.
III.
Chloride ions are behaving as ligands.
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
(Total 1 mark)
6.
Explain why copper is considered a transition metal while scandium is not.
(Total 3 marks)
7.
What is the ligand in the complex K3[Fe(CN)6]?
A.
CN–
B.
Fe3+
C.
K+
D.
[Fe(CN)6]3–
(Total 1 mark)
8.
The ten elements in the first-row d-block have characteristic properties and many uses.
(i)
State and explain the type of reaction that takes place between Fe3+ and H2O to form
[Fe(H2O)6]3+ in terms of acid-base theories.
(2)
IB Questionbank Chemistry
3
(ii)
Explain why [Fe(H2O)6]3+ is coloured.
(3)
(Total 5 marks)
9.
In which complexes does iron have an oxidation number of +3?
I.
[Fe(H2O)6]3+
II.
[Fe(H2O)5(CN)]2+
III.
[Fe(CN)6]3–
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
(Total 1 mark)
10.
Explain the origin of colour in transition metal complexes and use your explanation to suggest
why copper(II) sulfate, CuSO4(aq), is blue, but zinc sulfate, ZnSO4(aq), is colourless.
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(Total 4 marks)
IB Questionbank Chemistry
4
11.
Cu2+(aq) reacts with ammonia to form the complex ion [Cu(NH3)4]2+. Explain this reaction in
terms of an acid-base theory, and outline how the bond is formed between Cu2+ and NH3.
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(Total 3 marks)
12.
Which transition element, or compound of a transition element, is used as a catalyst in the
Contact process?
A.
Fe
B.
MnO2
C.
V2O5
D.
Ni
(Total 1 mark)
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(Total 3 marks)
IB Questionbank Chemistry
5
13.
Deduce the oxidation number of cobalt in the following species.
(i)
[Co(H2O)6]2+
(1)
(ii)
Co2(SO4)3
(1)
(iii)
[CoCl4]2–
(1)
(Total 3 marks)
14.
(i)
State the full electronic configurations of copper, Cu, and the copper(I) ion, Cu+.
(2)
(ii)
Explain why copper(II) compounds in aqueous solution are coloured whereas
scandium(III) compounds in aqueous solution are colourless.
(2)
(Total 4 marks)
15.
(a)
(i)
Draw the shape of the pz orbital using the coordinates shown.
(1)
IB Questionbank Chemistry
6
(ii)
State the electron configuration of Fe3+.
...........................................................................................................................
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(1)
(iii)
Define the term ligand.
...........................................................................................................................
...........................................................................................................................
(1)
(iv)
Explain why the complex [Fe(H2O)6]3+ is coloured.
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(3)
(v)
The element selenium (Z = 34) has electrons in the 4s, 3d and 4p orbitals. Draw an
orbital box diagram (arrow-in-box notation) to represent these electrons.
...........................................................................................................................
(1)
(Total 7 marks)
IB Questionbank Chemistry
7
16.
Which process is responsible for the colour of a transition metal complex?
A.
The absorption of light when electrons move between s orbitals and d orbitals
B.
The emission of light when electrons move between s orbitals and d orbitals
C.
The absorption of light when electrons move between different d orbitals
D.
The emission of light when electrons move between different d orbitals
(Total 1 mark)
17.
Transition elements form complexes such as [Fe(CN)6]4– and [FeCl4]–. Deduce the oxidation
number of iron in each of these complex ions.
[Fe(CN)6]4– ............................................................................................................................
[FeCl4]– ..................................................................................................................................
(Total 2 marks)
18.
Which salts form coloured solutions when dissolved in water?
I.
II.
III.
FeCl3
NiCl2
ZnCl2
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
(Total 1 mark)
IB Questionbank Chemistry
8
19.
Which combination is correct for the complex ion in [Co(NH3)4(H2O)Cl]Br?
Oxidation state of cobalt
Shape of the complex ion
Overall charge of the
complex ion
A.
+2
Octahedral
+2
B.
+3
Octahedral
–1
C.
+2
Octahedral
+1
D.
+2
Tetrahedral
+1
(Total 1 mark)
20.
Consider the transition metal complex, K3[Fe(CN)6].
(i)
Define the term ligand, and identify the ligand in this complex.
(1)
(ii)
Write the full electron configuration and draw the orbital box diagram of iron in its
oxidation state in this complex, and hence, determine the number of unpaired electrons in
this state.
(3)
(iii)
Explain why many transition metal d-block complexes are coloured.
(3)
(Total 7 marks)
IB Questionbank Chemistry
9