Brainscape's Knowledge GenomeTM

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


See full index

Biochem Y1 > transotion metals > Flashcards

transotion metals Flashcards

1
Q

what are transition metals

A

elements with partially filled d or f subshells

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

what are the tzy orientations for d orbitals

A

dxy, dzx and dyz

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

most stable oxidation state of Ca

A

2+

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

most stable oxidation state of Sc

A

3+

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

most stable oxidation state of Ti

A

4+

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

most stable oxidation state of V

A

+4

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

most stable oxidation state of Cr

A

+3

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

most stable oxidation state of Mn

A

+2

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

most stable oxidation state of Fe

A

+3

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

most stable oxidation state of Co

A

+2

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

most stable oxidation state of Ni

A

+2

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

most stable oxidation state of Cu

A

+2

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

most stable oxidation state of Zn

A

+2

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

Applications of transition metals

A

Fe is alloyed for structural materials
Cu is an electrical conductor
MnO2, NI and Zn make batteries
magnets
Cu and Co make catalysts
and Fe, Co and Zn make pharmaceuticals
pigments

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

factors that determine coordination number

A

size of central atom
steric interactions between ligands
electronic interactions

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

What are the posibble isometric positions for a compund with a CN number of 6

A

3 for planar hexagonal
3 for trigonal pryamidal
2 for octohedral

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

What are the types of opticalisomeration called when there are 3 of the same group and 3 of another

A

mer - planar
fac - non planar

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

types of distortion in CN 6 complexes

A

tetragonal distortion - stretching non polar axis (up + down , left and right) 4 fold rotation symmetry
axis triagonal distortion - diagonal along 3 fold rotation

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

When are tetrahedral complexes favoured

A

CN of 4 central atom is small and the ligands are large (eg halogen)

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

What dictates hard or soft coordination centres

A

polorisability
charge density (charge to size density)
nature od the bonding (ionic vs more covalent)

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

differences between hard and soft centres

A

polarisabilty - hard very little effect
- soft highly polarisable
Nature of bonding- hard highly ionic
- partly covalent in soft
form there strongest bond with O (which is hard) are hard
form strongest bonds with S or P which are soft are soft

20
Q

What assumptions does crystal field theory make

A

complexes are extreme hard interactions between central atom and negative ligands
bonding energy produced is through ionic interactions
the d orbitals interact with ligands to different extents making the orbital split into different groups based on energy

21
Q

How does crystal field theory suggest that repultion is minimised in ligands

A

large repulson between ligand and d orbital so the ligands form between the the split energy groups in order to minimise interaction with electron cloud repulsion

22
Q

how to calculate CFSE

A

low spin case the number of ligands x -0.4 + pairing energy P.
high spin case the first 3 ligands x -0.4 + the other number of ligands x +0.6

23
Q

why does low spin d6 only have 2P

A

pairing 2 electrons is required even when in the high spin conformation this is present in further higher conformations too.

24
Q

Whats the Jahn-Teller theorem

A

if electrons are unequally distributed among orbitals of the same energy then the complex distorts so the orbitals no longer have the same energy

25
Q

Which are the complexes that have a large complex distortion as told by the Jahn-Teller

A

d4 high spin, d7 low spin, d9 high spin complexes

26
Q

How does the Jahn-teller complex manifest in octohedral complexes

A

tetragonal elongation leads to less repulsion between apical ligands and occupied orbitals in the z direction

27
Q

When does it become energetically favourable to form a square planar complex instead of an octohedral

A

when the energy difference in d exceeds the pairing energy

28
Q

How to calculate the delta T value

A

the same as CFSE but without the pairing energy and the number of pairs swaps (2 sets on the lower energy half and 3 on the top) 0.6 is negative and for the bottom set 0.4 is positive and for the top set

29
Q

how to calculate wave length

A

lamda = planck constant x speed of light / delta O

30
Q

how is absorbance measured

A

A = molar absorption coefficient x cooncentration x path length

31
Q

how the same metal core with the same oxidation state have different colour

A

the ligands binded
larger ligands = higher energy light absorbed so red
smaller ligands = lower energy light absorbed so blue

32
Q

what is the spectrochemical field order

A

I- < Br- < S2- < SCN- (s) < Cl- < F- < OH- < CH3CO2-< H2O < SCN- (n) < pyridine < NH3 < en < bipyridine < NO2- <CN- < CO This end is strong field

33
Q

Factors affecting how much the crystal field splits (colour stuff)

A

the nature of the ligands (spectrochemical series) , the coordination geometry and number of ligands,
the nature of the metal ion

34
Q

when colour transitions occur whats causing them

A

oscillating electromagnetic fields

35
Q

what is the probability of a transition dependent upon

A

a colour is allowed to transition to a more intense colour but not a lighter one
laporte selection rule in an allowed transition the quantumnumber must change by add or minus 1 so d->d transitions are forbidden
parity selection rule (symmetry selection rule) S and D orbitals have a centre of symmetry but p orbital does not
so D and S are gerade (g) whereas P which doesnt have a line of symmetry is ungerade (u) the d orbitals in a octohedral field t2g and eg as these are both gerade transitons between them are forbidden as well as u -> utransitions
spin selection rule: an electron can move from ground state to excited state to an empty orbital but not to form a pair
charge transfer transitions are allowed - electrons move temporarily from ligand orbitals to orbitals with metal character intense colour change

36
Q

When does the magnetic field have influence on complexes

A

when there are unpaired electrons they will align with the magnetic field which is paramagnetism and the strength of this is dependent upon how many unpaired electrons there are

37
Q

how do you calculate the magnetic moment

A

calculated using spin only equation
mu eff = root n(n+2) where n = the number of unpaired electrons

38
Q

What is diamagnetism

A

its the effect of the magnetic field on paired electrons which does occur but is smaller

39
Q

how to work out whether a complex was high spin or low spin from magnetism

A

calculate the magnetic moment
compare this to a literature know value and judge accordingly

40
Q

what is ferromagnetism

A

an increased degree of magnetism where the spins spontaneously realign in the same direction below critical temperature (curie)

41
Q

What are the different terms used to refer to the kinetics of a reaction and their thermodynamic basis?

A

thermodynamically unstable complexes that survive for long periods are called inert
complexes that form rapid equalibriums are called labile

42
Q

how does a lower activation energy increase rate of reaction

A

stabilisation of the transitions state
destabilisation of the ground state

43
Q

what are the major factors affecting rate

A

the oxidative state of the metal
the distribution of 3d electrons

44
Q

What reflects the thermodynamic stability of a compound

A

equilibrium formation constant (Kf)or dissociation constant (Kd) for a reaction of a metal cation + a ligand

45
Q

How to workout the overall formation constant

A

Bn is the easiest to find by finding the ln of all the constituent reaction constants in log form added together to find the lnBn which can then be undone using exponentials

46
Q

Enthalpic effects on the stability of complexes

A

bond strength
effect of CFSE
steric repulsions between ligands
electrostatic repulsion between ligands

47
Q

entropic effects on the stability of complexes

A

changes in solvation
number and size of chelate rings

48
Q

what is the chelate effect

A

complexes with multidetate ligands are more stable then equivalent complexes with monodentate ligands

Biochem Y1 (11 decks)

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