Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

chem > transition metals > Flashcards

transition metals Flashcards

1
Q

where are transition metals found

A

d block

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are transition metals

A

d block elements that can form one or more stable ions with incompletely filled d orbitals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what d block elements are not transition metals

A

scandium and zinc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why isn’t scandium a transition metal

A

scandium only forms one ion Sc³⁺ which has a empty d sub shell
it has configuration [Ar]3d¹4s² when it loses three electrons it has configuration of [Ar]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

why isnt zinc a transition metal

A

zinc only forms Zn²⁺ which has a full d sub shell
its configuration is [Ar] 3d¹⁰4s² when it loses two electrons it has a full 3d subshell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

transition metals have variable … numbers

A

oxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

transition metals can have variable oxidation numbers because they form multiple …

A

stable ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what needs to happen to form a compound or a complex containing an ion with a certain oxidation number

A

energy given out when complex is formed has to be bigger than the energy taken to remove outer electrons and form the ion (the ionisation energy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

transition metals form ions from losing electrons from which subshells

A

4s and 3d

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

why does it take similar amounts of energy to remove an electron from 4s sub shell and the 3d sub shell

A

because the 4s sub shell and the 3d sub shell have similar energy levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what happens to the energy released when ions form complexes with increasing ionic charge

A

increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is a complex ion

A

metal ion surrounded by dative covalently (coordinately) bonded ligands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is a ligand

A

a atom ion or molecule that donates a pair of electrons to a central metal atom or ion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what must a ligand have

A

at least one lone pair of electrons or it wont have anything to form a dative covalent bond with

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

ligands with one lone pair are called

A

monodentate
eg. H₂O: :NH₃ :Cl ⁻ :OH⁻

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

ligands with two lone pairs are called

A

bidentate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

example of bidentate ligand

A

1,2-diaminoethane
NH₂CH₂CH₂NH₂

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

which ligands can form two dative covalent bonds with a metal ion

A

bidentate ligands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

ligands with more than two lone pairs are called

A

multidentate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

EDTA⁴⁻ has six lone pairs what ligand is it and how many dative covalent bonds can it form

A

hexadentate ligand/multidentate
and can form six dative covalent bonds with metal ion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does haemoglobin do

A

transport oxygen around the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what metal complex is haemoglobin

A

iron(II)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what type of ligand is haemoglobin

A

a multidentate ligand called a haem group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is a haem group made up of

A

a ring containing 4 nitrogen atoms with iron at the centre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

the overall charge on a complex ion is its

A

oxidation number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

where would you put the charge on a complex ion

A

outside the square brackets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

oxidation number of the metal ion =

A

total oxidation number - sum of the charges of the ligand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

work out the charge of the metal ion iron in [Fe(CN)6]⁴⁻

A

total oxidation number = -4
CN⁻ ligand charge = -1
iron oxidation number = -4 - (6 x -1 ) = +2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what is the coordination number

A

number of dative covalent (coordinate) bonds formed with central metal ion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what are usual coordinate numbers

A

6 and 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

if a ligand is small what is the usual coordinate number

A

6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

if a ligand is larger what is the usual coordinate number

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

why are the ligands positioned as far away from each other

A

because bonding electrons in dative covalent bond of a complex repel each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is the shape and bond angle in six fold coordination

A

octahedral shape and all bond angles are 90

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what is th shape and bond angle in four fold coordination

A

tetrahedral shape bong angles are 109.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is the other occasional four fold coordination

A

square planar where bond angles are 90
eg cis-platin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

cis/trans isomerism a form of

A

E/Z isomerism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

which shape complex ions can show cis/trans isomerism

A

square planar and octahedral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what happens to the groups in cis isomers

A

they are on the same side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what happens tot he groups in trans isomers

A

same groups opposite each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what metal complex is cis-platin

A

platinum(II)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what ligands are on cis-platin

A

two chloride ions and two ammonia molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what shape is cis-platin

A

square planar and so has bond angles of 90

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what is cis-platin used for

A

anti cancer drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

why cant trans-platin be given to patients being treated for cancer

A

its toxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what happens to 3d orbital when ligands bond to the central ion

A

3d orbital splits into two different energy levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what orbitals do electrons tend to occupy

A

the lower orbitals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what do electrons need to jump up to higher electron orbitals

A

energy equal to the energy gap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

where do electrons get the energy to jump up to higher orbitals

A

from visible light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

for larger energy gaps does the frequency of light absorbed increase or decrease

A

increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

what affects the size of the energy gap

A

central metal ion
the central metal ions oxidation number
the ligands
coordination number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what happens to the rest of the frequencies of light that are not absorbed

A

they are transmitted or reflected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what do the transmitted or reflected frequencies of light do

A

combine to make the complement of the colour of the absorbed frequencies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

from red to purple light what happens to the frequency

A

frequency increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

what is the complimentary of red

A

cyan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

what is the complementary of yellow

A

blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

what is the complementary of green

A

magenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

what is the complementary of cyan

A

red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

what is the complementary of blue

A

yellow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

what is the complementary of magenta

A

green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

if there are no 3d electrons what does this mean in terms of energy

A

no energy can be absorbed

62
Q

if no energy can be absorbed what colour will the compound be

A

white or colourless

63
Q

when solid containing transition metal ion is dissolved in water what happens

A

transition metal will form aqueous complex in solution

64
Q

what happens in a aqueous water complex

A

metal ion is surrounded by water ligands

65
Q

what can the colour of the aqueous solutions do

A

help us identify transition metal that is present

66
Q

what colour is Mn+7/MnO₄⁻

A

purple

67
Q

what colour is chromium+6/Cr₂O₇²⁻

A

orange

68
Q

what colour is magnese+6/MnO₄²⁻

A

green

69
Q

what colour is vanadium+5/VO₂⁺

A

yellow

70
Q

what colour is vandium+4/VO²⁺

A

blue

71
Q

what colour is titanium+3/Ti³⁺

A

purple

72
Q

what colour is vanadium+3/V³⁺

A

green

73
Q

what colour is chromium+3/Cr³⁺

A

green

74
Q

what colour is iron+3/Fe³⁺

A

yellow

75
Q

what colour is titanium+2/Ti²⁺

A

violet

76
Q

what colour is vanadium+2/V²⁺

A

violet

77
Q

what is the colour of magnese+2/Mn²⁺

A

pale pink

78
Q

what is the colour of iron+2/Fe²⁺

A

pale green

79
Q

what colour is cobalt+2/Co²⁺

A

pink

80
Q

what colour is nickel+2/Ni²⁺

A

green

81
Q

what colour is copper+2/Cu²⁺

A

pale blue

82
Q

how many oxidation numbers can vanadium exist in in solution

A

four

83
Q

each reduction reaction has its own

A

reducing potential

84
Q

reduction potentials are another name for

A

electrode potentials

85
Q

reduction potentials allow you to work out if

A

redox reactions involving transition metals are likely to happen

86
Q

what ion does chromium form with oxygen

A

chromate(VI) ions [CrO₄²⁻]
dichromate(VI) ions [Cr₂O₇²⁻]

87
Q

why are chromate(VI) ions [CrO₄²⁻], dichromate(VI) ions [Cr₂O₇²⁻] good oxidising agents

A

because they are easily reduced to Cr³⁺

88
Q

what colour are Cr³⁺ ions when surrounded by 6 water ligands

A

violet

89
Q

why will Cr³⁺ ions in solution sometimes look green

A

because the water ligands can be substituted with impurities eg Cl⁻

90
Q

write the reaction of of dichromate (VI) ions/Cr₂O₇²⁻ with zinc and dilute acid

A

Cr₂O₇²⁻(aq) + 14H⁺(aq) + 3Zn(s) ⟶ 3Zn²⁺(aq) + 2Cr³⁺(aq) + 7H₂O(l)

91
Q

write the second reaction of zinc reducing Cr³⁺

A

2Cr³⁺(aq) + Zn(s) ⟶ Zn²⁺(aq) + 2Cr²⁺(aq)

92
Q

why do you need to use inert atmosphere when reacting zinc with Cr³⁺

A

Cr²⁺ is so unstable that it oxidises straight back to Cr³⁺ in air

93
Q

reaction of Cr³⁺ with hydrogen per oxide in alkaline solution

A

2Cr³⁺(aq) + 10OH⁻(aq) + 3H₂O₂(aq) ⟶ 2CrO₄²⁻(aq) + 8H₂O(l)

94
Q

reaction of 2CrO₄²⁻ with acid

A

2CrO₄²⁻(aq) + 2H⁺(aq) ⇌ Cr₂O₇²⁻(aq) + H₂O(l)

95
Q

what happens when you mix aqueous solution of chromium(II) ions with aqueous sodium hydroxide or aqueous ammonia

A

you get chromium hydroxide precipitate

96
Q

[Cr(H2O)6]³⁺(aq) + 3OH⁻(aq)⟶

A

Cr(OH)3(H₂O)₃ + 3H₂O(l)

97
Q

[Cr(H₂O)₆]³⁺(aq) + 3NH₃(aq)⟶

A

Cr(OH)₃(H₂O)₃ + 3NH₄⁺(aq)

98
Q

what colour is chromium hydroxide precipitate/[Cr(OH)₃(H₂O)₃]

A

a grey green precipitate

99
Q

what does amphoteric mean

A

can react as a acid or base

100
Q

chromium hydroxide is amphoteric so

A

it reacts with both acids and bases

101
Q

chromium hydroxide reacts with both acids and bases so its

A

amphoteric

102
Q

[Cr(OH)₃(H₂O)₃] +3H⁺⟶

A

[Cr(H₂O)₆]³⁺

103
Q

[Cr(OH)₃(H₂O)₃] + 3OH⁻⟶

A

[Cr(OH)₆]³⁻ + 3H₂O

104
Q

if you add excess sodium hydroxide to chromium hydroxide precipitate the H₂O ligands

A

depropanate

105
Q

If you add acid to the chromium hydroxide precipitate, the OH⁻ ligands

A

protonate

106
Q

if you add excess NH₃ to chromium hydroxide precipitate

A

a ligand exchange reaction occurs

107
Q

Cr(OH)₃(H₂O)₃ + 6NH₃(aq)⟶

A

[Cr(NH₃)₆]³⁺(aq) + 3OH⁻(aq) + 3H₂O(l)

108
Q

what is the first steps in making chromium (II) ethanoate

A

*orange sodium dichromate is reduced with zinc in acid solution to form green solution
*Cr₂O₇²⁻(aq) + 14H⁺(aq) +3Zn(s)⟶3Zn²⁺(aq) + 2Cr³⁺(aq) +7H₂O(l)
*and then give blue solution of Cr²⁺ ions
*2Cr³⁺(aq) + Zn(s) ⟶ 2Cr²⁺(aq) + Zn²⁺(aq)

109
Q

what is the second step in making chromium (II) ethanoate

A

*sodium ethanoate mixed with solution and red precipitate of chromium (II) ethanoate
*2Cr²⁺(aq) + 4CH₃COO⁻(aq) + 2H₂O(l) ⟶ Cr₂(CH₃COO)₄(H₂O)₂

110
Q

Cr²⁺ are very easily oxidised what should you do to stop them being oxidised

A

*do experiment in inert atmosphere eg nitrogen
*remove air and all oxygen from all the liquids by bubbling nitrogen through them

111
Q

when ligands are swapped and are of the same size what happens to coordination number and the shape of the complex

A

coordination number does not change and neither does the shape

112
Q

if a small uncharged ligand is substituted for large charged ligand what happens to coordination number and change of shape

A

there’s a change of shape and coordination number

113
Q

[Cr(H₂O)₆]³⁺(aq) + 6NH₃(aq) ⇌
and what is the colour change

A

[Cr(NH₃)₆]³⁺(aq) + 6H₂O(l)
*dark green to purple

114
Q

[Cu(H₂O)₆]²⁺(aq) + 4Cl⁻(aq) ⇌
and what is the colour change

A

[CuCl₄]²⁻(aq) + 6H₂O(l)
*pale blue to yellow

115
Q

[Co(H₂O)₆]²⁺(aq) + 4Cl⁻(aq) ⇌
and what is the colour change

A

[CoCl₄]²⁻(aq) + 6H₂O(l)
pale pink to blue

116
Q

[Cu(H₂O)₆]²⁺(aq) + 4NH₃(aq) ⇌
and what is the colour change

A

[Cu(NH₃)₄(H₂O)₂]²⁺(aq) + 4H₂O(l)
pale blue to deep blue

117
Q

how is carboxyhemoglobin formed

A

oxygen or water molecule in haemoglobin is replaced in ligand exchange reaction with carbon monoxide

118
Q

why does carbon monoxide poisoning happen

A

because carbon monoxide forms strong dative covalent bonds with iron and doesn’t readily exchange with oxygen or water ligands meaning haemoglobin can’t transport oxygen

119
Q

more stable complexes have a positive or negative entropy change

A

positive

120
Q

why do ligand exchange reactions have small enthalpy change reactions

A

dative bonds are broken and formed strength of bonds broken is similar to the strength of the new bonds so enthalpy change is usually small

121
Q

why does entropy increase when mono dentate ligands substituted with bi dentate ligands or multi dentate ligands

A

because when they are substituted the number of particles in solution increases the more particles the greater the entropy reactions with increase in entropy are more likely to happen

122
Q

which reaction is more likely to happen a reaction with a increase in entropy or a reaction with a decrease in entropy

A

the reaction with a increase In entropy

123
Q

when EDTA⁴⁻ replaces mono dentate ligand why does the complex become more stable

A

because the number of particles in solution increases, the more particles the greater the entropy, the greater the entropy the more stable the complex formed

124
Q

what characteristic do transition element hydroxides have

A

brightly coloured precipitates

125
Q

what happens when you mix aqueous solution of transition element ions with aqueous sodium hydroxide and or aqueous ammonia

A

water ligands are deprotonated in acid base reaction and you get a coloured hydroxide precipitate

126
Q

how can you reverse transition element ions with aqueous sodium hydroxide or aqueous ammonia

A

adding an acid to hydroxide percipitate as the hydroxide ligands will protonate and precipitate will dissolve as soluble meta aqua ions

127
Q

[Cu(H₂O)₆]²⁺(aq) + 2OH⁻(aq)⟶
and what is the colour change

A

Cu(OH)₂(H₂O)₄](s) + 2H₂O(l)
pale blue solution to blue precipitate

128
Q

[Cu(H₂O)₆]²⁺(aq) + 2NH₃(aq)⟶
and what is the colour change

A

Cu(NH₃)₂(H₂O)₄ + 2NH₄⁺(l)
pale blue solution to blue precipitate

129
Q

Cu(OH)₂(H₂O)₄ + 4NH₃(aq) ⟶ [Cu(NH₃)₄(H₂O)₂]²⁺(aq) + 2OH⁻(aq) + 4H₂O(l)
is what type of reaction

A

ligand exchange reaction

130
Q

Cu(OH)₂(H₂O)₄ + 4NH₃(aq) ⟶
and what is the colour change

A

[Cu(NH₃)₄(H₂O)₂]²⁺(aq) + 2OH⁻(aq) + 4H₂O(l)
blue precipitate to deep blue solution

131
Q

[Fe(H₂O)₆]²⁺(aq) + 2OH⁻(aq) ⟶
and what is the colour change

A

Fe(OH)₂(H₂O)₄ + 2H₂O(l)
pale green solution to green precipitate

132
Q

[Fe(H₂O)₆]²⁺(aq) + 2NH₃(aq) ⟶
and what is the colour change

A

Fe(OH)₂(H₂O)₄ + 2NH₄⁺(aq)
pale green solution to green precipitate

133
Q

[Fe(H₂O)₆]³⁺(aq) + 3OH-(aq) ⟶
and what is the colour change

A

Fe(OH)₃(H₂O)₃ + 3H₂O(aq)
yellow solution to an orange precipitate

134
Q

[Fe(H₂O)₆]³⁺(aq) + 3NH₃(aq) ⟶
and what is the colour change

A

Fe(OH)₃(H₂O)₃ + 3NH₄⁺(aq)
yellow solution to orange precipitate

135
Q

[Co(H₂O)₆]²⁺(aq) + 2OH⁻(aq) ⟶
and what is the colour change

A

Co(OH)₂(H₂O)₄ + 2H₂O(l)
pale pink solution to a blue precipitate which turns brown on standing

136
Q

[Co(H₂O)₆]²⁺(aq) + 2NH₃(aq) ⟶
and what is the colour change

A

Co(OH)₂(H₂O)₄ + 2NH₄⁺(aq)
pale pink solution to a blue precipitate which turns brown on standing

137
Q

Co(OH)₂(H₂O)₄ + 6NH₃(aq) ⟶ [Co(NH₃)₆]²⁺(aq) + 2OH⁻(aq) + 4H₂O(l)
is a

A

ligand exchange reaction

138
Q

Co(OH)₂(H₂O)₄ + 6NH₃(aq) ⟶
what’s the colour change

A

[Co(NH₃)₆]²⁺(aq) + 2OH⁻(aq) + 4H₂O(l)
the blue precipitate dissolves to form yellow brown solution

139
Q

why do transition metals make good catalyst

A

because they can change oxidation number by gaining or losing electrons within their d orbitals this means they can transfer electrons to speed up reactions

140
Q

V₂O₅ + SO₂ ⟶ V₂O₄ + SO₃
V₂O₄ + ½O₂ ⟶ V₂O₅
what is happening here

A

*vanadium oxidises SO₂ to SO₃ and is reduced itself
*the reduced catalyst is oxidised by oxygen gas back to its original state
*catalyst ready to do process all over again

141
Q

what are homogenous catalyst

A

catalyst in the same state as the the reactants

142
Q

what state is a homogenous catalyst usually

A

an aqueous catalyst for a reaction between two aqueous solutions

143
Q

how do homogenous catalyst work

A

work by combining with the reactants to form intermediate species and then react to form products and reform the catalyst

144
Q

what is true about the energy needed to form the intermediate species which then reacts to form the products and reform the catalyst

A

the energy needed to form the intermediate is lower than that needed to make the product directly from reactants

145
Q

why is the catalyst always able to catalyse the reaction

A

because its always reformed

146
Q

why is the reaction between iodide ions and peroxodisulfate (S₂O₈²⁻) really slow

A

because the ions are both negatively charged so they repel each other so its unlikely they’ll collide and react

147
Q

why doe the reaction between peroxodisulfate (S₂O₈²⁻) ad iodide ions become faster when you add Fe²⁺ ions

A

because each stage involves a positive and negative ions so there’s no repulsion

148
Q

write the reactions between peroxodisulfate (S₂O₈²⁻) ad iodide ions when you add Fe²⁺ ions

A

*S₂O₈²⁻(aq) + 2Fe²⁺(aq) ⟶ 2Fe³⁺(aq) + 2SO₄²⁻(aq)
*2Fe³⁺(aq) + 2I⁻(aq) ⟶I₂(aq) + 2Fe²⁺(aq)

149
Q

*S₂O₈²⁻(aq) + 2Fe²⁺(aq) ⟶ 2Fe³⁺(aq) + 2SO₄²⁻(aq)
*2Fe³⁺(aq) + 2I⁻(aq) ⟶I₂(aq) + 2Fe²⁺(aq)
explain what’s going on

A

*first the Fe²⁺ ions are oxidised to Fe³⁺ ions by S₂O₈²⁻
*the newly formed intermediate Fe³⁺ ions now easily oxidise the I⁻ ions to iodine and the catalyst is regenerated

150
Q

what is autocatalysis

A

Autocatalysis the term used to describe a reaction which is speeded up by a product which acts as a catalyst for the reaction

151
Q

how can you reduce Cr₂O₇²⁻ to Cr³⁺ and Cr²⁺

A

using zinc in acidic conditions

chem (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions