TOPIC 15 - Transition metals Flashcards
1
Q
What is a transition element?
A
2
Q
Why isn’t scandium a transition element?
A
3
Q
Why isn’t zinc a transition element?
A
4
Q
In what order of orbitals do transition elements loose electrons?
A
4s looses and gains electrons first, 3d looses/gains second.
5
Q
Why do transition elements have various oxidation states?
A
Electrons in 4s and 3d orbitals have similar energy levels so similar amounts of energy are needed to create different ions.
6
Q
What is the colour of V 2+ (aq)?
A
Violet
7
Q
What is the colour of V 3+ (aq)?
A
Green
8
Q
What is the colour of VO 2+ (aq)?
A
Blue
9
Q
What is the colour of VO2 + (aq)?
A
Yellow
10
Q
What is the colour of Cr 3+ (aq)?
A
Green
(actually violet when surrounded by 6H2O but some ligands are usually substituted an so usually appears green)
11
Q
What is the colour of Cr2O7 2- (aq)?
A
Orange
12
Q
What is the colour of Mn 2+ (aq)?
A
Pale pink
13
Q
What is the colour of MnO4 2- (aq)?
A
Green
14
Q
What is the colour of MnO4 - (aq)?
A
Purple
15
Q
What is the colour of Fe 2+ (aq)?
A
Pale green
16
Q
What is the colour of Fe 3+ (aq)?
A
Yellow
17
Q
What is the colour of Co 2+ (aq)?
A
Pink
18
Q
What is the colour of Ni 2+ (aq)?
A
Green
19
Q
What is the colour of Cu 2+ (aq)?
A
Blue
20
Q
What is the colour of Ti 2+ (aq)?
A
Violet
21
Q
What is the colour of Ti 3+ (aq)?
A
Purple
22
Q
What is the colour of CrO4 2- (aq)?
A
Yellow
23
Q
What is the colour of Cr 2+ (aq)?
A
Blue
24
Q
What is a complex ion?
A
25
What is a ligand?
26
Name 4 monodentate ligands
27
Name 2 bidentate ligands
28
Name a multidentate ligand
29
What is the coordination number od a complex ion?
30
How many H2O, NH3 or OH- ligands can you usually fit around a central metal ion?
6
31
How many Cl- ligands can you usually fit around a central metal ion?
4
32
How many ethanedioate / ethane-1,2,diamine ligands can you usually fit around a central metal ion?
3
33
What shapes/bond angle do complexes with coordination number of 6 usually have?
Octahedral shape
90º bond angle
34
What shapes/bond angle do complexes with coordination number of 4 usually have?
Tetrahedral (109.5º)
Square planar (90º)
35
What is the shape and bond angles of the anticancer drug cis-platin?
36
What is the structure of the ion complex in haemoglobin? Where does each ligand comes from in the ion complex?
37
How does haemoglobin transport oxygen?
38
Why is carbon monoxide poisonous?
39
Do complexions exhibit optical / stereoisomerism ?
Yes
40
Why are complex ions from transition metals coloured?
1. Ligand bonds increase the energy level of some d orbitals.
2. Therefore the d orbitals are splitted in energy levels (the amount of change depends on the ligand, central ion etc.)
3. Electrons absorb energy from photons to move to the higher energy d orbitals.
4. The frequency of the photon absorbed is specific to that amount of energy.
5. The frequencies that are not absorbed combine to reflect the complementary colour of the one being absorbed.
41
Can complexes that have a full or empty 3d subshell be coloured in the same way as transition elements?
No. Since electrons can't move to the higher energy d orbitals (because they're already full or because there's none in the d subshell to start), and therefore can't absorb a specific wavelength.
42
Which ion is more stable?
Zn 2+ is more stable, since it hasa lower Eº for its reduction.
43
At which value of Eº are reactions feasible?
+ve
44
Although the reduction of Cr 3+ to Cr 2+ using zinc ions has a positive Eº, why doesn't it happen?
Cr 2+ is very unstable and is readily oxidised back to Cr3+ using oxygen in the air.
45
Chromate (VI) ions (CrO4 2-) exist in equilibrium with dichromate (VI) ions (Cr2O4 2-). Given the equation, what would be seen upon addition of acid?
Equilibrium shifts to the right so more dichromate ions are produced so colour change is from yellow to orange.
46
Are chromium hydroxides acidic, basic, or amphoteric?
Amphoteric.
47
What is the equation and colour change for the reaction of chromium hexaqua with small amounts of hydroxide?
48
What is the equation and colour change for the reaction of chromium hexaqua with small amounts of NH3?
49
Write equations to show that Cr(H2O)3(OH)3 is amphoteric.
50
What happens when we add excess NH3 to solid Cr(H2O)3(OH)3 ?
51
How is crhomium (II) ethanoate, Cr2(CH3COO)4(H2O)2 , synthesised?
52
What is the equation for the reaction of hexa-aqua cobalt complex with excess ammonia?
53
What is the equation for the reaction of hexa-aqua copper complex with excess ammonia?
54
What is the equation for the reaction of hexa-aqua cobalt complex with Cl-?
55
Which are more stable: multidentate ligands complexes or monodentate ligands compexes?
Multidentate ligands complexes are more stable.
56
What is the equation of hexaqua Fe3+ with CN-?
57
What is the equation for the reaction of hexa-aqua copper complex with ethanediamine?
58
What is the chelate effect?
When we susbtitute monodentate ligands with bidentate/multidentate ligands we create a solutio with more particles in it (i.e. H2O that were bonded to the ligand are now free) and therefore entropy increases, so the newly formed complex is more stable.
59
Are EDTA 4- complexes stable?
Yes - very stable.
| (due to the chelate effect)
60
What is the equation for the reaction of cromium (III) hexaqua complex with EDTA 4- ?
61
What colour change would be seen?
62
What is the complex ion + colour of Cu 2+ in aqueous solution?
63
What is the complex ion + colour of Fe 2+ in aqueous solution?
64
What is the complex ion + colour of Fe 3+ in aqueous solution?
65
What is the complex ion + colour of Co 2+ in aqueous solution?
(Co(H2O)6) 2+
Pink
66
What is the complex ion + colour of Cu 2+ with small amount of OH (aq) / NH3 (aq) ?
67
What is the complex ion + colour of Fe 2+ with small amount of OH (aq) / NH3 (aq) ?
68
What is the complex ion + colour of Fe 3+ with small amount of OH (aq) / NH3 (aq) ?
69
What is the complex ion + colour of Co 2+ with small amount of OH (aq) / NH3 (aq) ?
70
What is the complex ion + colour of Cu 2+ with excess of OH- (aq)?
71
What is the complex ion + colour of Fe 2+ with excess of OH- (aq)?
72
What is the complex ion + colour of Fe 3+ with excess of OH- (aq)?
73
What is the complex ion + colour of Co 2+ with excess of OH- (aq)?
74
What is the complex ion + colour of Cu 2+ with excess of NH3 (aq)?
75
What is the complex ion + colour of Fe 2+ with excess of NH3 (aq)?
76
What is the complex ion + colour of Fe 3+ with excess of NH3 (aq)?
77
What is the complex ion + colour of Cu 2+ with excess of NH3 (aq)?
78
What is the equation for the reaction between Cu 2+ (aq) with:
little amount of OH-?
little amount of NH3?
79
What is the equation for the reaction between Fe 2+ (aq) with:
little amount of OH-?
little amount of NH3?
80
What is the equation for the reaction between Fe 3+ (aq) with:
little amount of OH-?
little amount of NH3?
81
What is the equation for the reaction between Co 2+ (aq) with:
little amount of OH-?
little amount of NH3?
82
How does Vanadium V Oxide catalyse SO2 to SO3 in the contact process?
83
What effect on heterogeneous catalysts can impurities have?
84
How can the iron catalyst be poisoned in the haber process?
85
How do lead impurities poison catalysts in cars?
86
How do FE2+ ions catalyse the reaction between peroxodisulfate ions (S2O8 2-) and iodide ions (I-) ?
87
How is the reaction between C2O4 2- and MnO4 - an example of autocatalysis?
88
