Transition metals Flashcards

1
Q

TM & d block elements?

A

all TM are d block elements but not all d block elements are TM

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2
Q

d block elements with a strange electron arrrangement?

A

Cr and Cu

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3
Q

Cr electron arrangement ?

A

[Ar]4s13d5 - electron moves from 4s to 3d orbital

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4
Q

Cu electron arrangement?

A

[Ar] 4s13d10

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5
Q

Why does Cr have this arrangement?

A

• repulsion between the 2 4s e- causes e- to move to empty 3d subshell

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6
Q

Why does Cu have this arrangement?

A

e- moves from 4s orbital to 3d, making 3d subshell full which makes Cu more stable

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7
Q

when d block elements form ions which electrons are lost?

A

4s lost first bc they’re the outer shell electrons

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8
Q

first row d block elements that are not TM?

A

Scandium and zinc

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9
Q

what is a TM?

A

element that forms at least 1 ion w a partially filled d subshell

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10
Q

Sc ion always has an ox no of

A

+3

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11
Q

Zn ion always has an ox number of

A

+2

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12
Q

Why is the most common ox state for TM +2?

A

2 4s e- lost

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13
Q

Cu (s) colour?

A

red/ brown solid

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14
Q

KMnO4 colour and use?

A
  • potassium manganate (VII)
  • purple
  • redox titrations
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15
Q

CuSO4 colour and use?

A
  • blue
  • crystal growing
  • testing for amines
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16
Q

Na2Cr2O7 colour and use?

A
  • orange

* oxidation of primary and secondary alcohols

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17
Q

AgNO3 colour and use?

A
  • colourless

* testing for halide ions

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18
Q

FeBr3 colour and use?

A
  • yellow

* halogen carrier

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19
Q

TM general?

A
  • exist in >1 oxidation state
  • form coloured ions
  • act as catalysts
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20
Q

BZ y axis?

A

no. of particles

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21
Q

Ni as a catalyst?

A
  • heterogeneous
  • hydrogenation of alkenes
  • producing margarine
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22
Q

MnO2 as a catalyst?

A
  • heterogeneous

* decomposition of H2O2 into H2O and O2

23
Q

Fe as a catalyst?

A
  • hetero
  • haber process
  • producing NH3
24
Q

Vanadium pentoxide, V2O5 as a catalyst?

A
  • hetero
  • contact process - SO2 + 1/2O2 ➡ SO3
  • producing sulphuric acid
25
Cu as a catalyst?
* hetero * oxidation of ethanol to form ethanal * CH3CH2OH ➡ CH3CHO + 2H+ + 2e- * Cu2+ + 2e- ➡ Cu(s)
26
unusual for het to be
redox
27
Co2+ as catalyst?
* homogeneous * sodium potassium tartrate and H2O2 * produces CO2
28
Fe2+ as a catalyst?
* homogeneous catalyst * iodide and peroxodisulphate ions * produces iodine
29
Heterogenous catalysis
1) Adsorption - reactants form weak bonds to catalyst - O bonds w catalyst by donating lone pair of e- 2) weakens bonds within H2O2 + other bonds form - reaction occurs. Reaction takes place on surface of catalyst • lower Ea bc reactants held in correction orientation for reaction or weaker bonds 3) desorption - bonds between catalyst and product break. Product leaves catalyst surface and catalyst can b resued
30
heterogeneous catalysis is when
* catalyst and reactants in diff states | * TM can act as het catalysts bc empty d orbitals so can accept LP of e-
31
TM have a vacant ?
d orbitals so lone pairs can be donated to the TM
32
TM form
gelatinous precipitates
33
homogeneous catalysis?
TM can easily change ox state - can exist in diff oxidation states
34
Homogeneous catalysis equations?
* break equation down into oxidation and reduction equations * oxidise/ reduce catalyst * if O, goes w reduction equation * do the opp * pair again
35
what other impact could a catalyst have?
• w a catalyst, may have a higher cell potential than uncatalysed, more likely to occur
36
molecular ion?
ion w covalent bond inside, is charged
37
dative covalent bond?
lone pair is donated by 1 atom - lone pair needed and empty orbital needed
38
Complex ions involve
DCB and ligands
39
ligands?
* have a LP of electrons, which they donate to form dative covalent bonds to TM ions. This is then known as a complex ion * can be neutral or an anion - negatively charged ion
40
lone pairs in ligand determines?
how many bonds ligands can form
41
bidentate ligands have ? lone pairs
2
42
e.g. of hexadentate ligand?
EDTA4-
43
what is the co-ordination number?
number of dative covalent bonds to TM ion. CN usually 6, octahedral shape
44
when is the CN 4?
* When halide ions are the ligand, tetrahedral shape | * G10 metals, square planar shape
45
when is the CN 2?
* Ag | * Linear
46
ligand substitution?
a ligand in a complex ion can be substituted by another ligand. The replacement ligand forms a more stable complex ion
47
monodentate is the ?
easiest to remove in substitution. Hexadentate are the hardest bc wraps itself around TM
48
when forming precipitate?
can use ion(aq) but when forming complex ion must write as [ion(water)6}charge
49
same result after adding few drops NaOH and ?
a few drops of aq ammonia - prec forms
50
only ? changes when excess NaOH is added?
Cr3+. Green solution forms, precipitate dissolves
51
why do precipitates disappear when acid is added?
bases so react w acid to form, salt and water
52
Cr3+ reaction?
* when NaOH added: green gel prep forms * excess: clear green solution - [Cr(OH)6]3- forms * w acid: reaction reversed - Cr(OH)3 forms
53
darkening on surface is due to
oxidation
54
Homogeneous catalysis?
• in solution