transition metals

Question 1

what is a transition metal?

Answer 1

d block element that can form atleast stable 1 ion with a partially filled d sub shell

Question 2

why are scandium and zinc not transition elements

Answer 2

scandium only forms one ion Sc3+ which has no electrons on the d shell
zinc only forms one ion Zn2+ which has a full d shell as the 2 electrons are taken from the S block

Question 3

why do transition metals have variable oxidation states?

Answer 3

3d and 4s orbitals are very close as a result the electrons lost and gained use a similar amount of energy when forming ions

Question 4

what transition metals are green

?

Answer 4

V(3+)
Ni(2+)
pale green
Co(2+)

Question 5

what transition metals are blue?

Answer 5

Cu(2+)

VO(2+)

Question 6

what transition metals are yellow?

Answer 6

Fe(3+)

VO2 (+)

Question 7

what transition metals are pink

Answer 7

mn(2+)

Cu(2+)

Question 8

what transition metals are voilet/purple

Answer 8

MnO4(-)

Question 9

what is a complex ion?

Answer 9

when a metal ion is surrounded by ligands which have lone pairs and can therefore bonded dative covalently (coordinate)

Question 10

what is a monodentate?

Answer 10

ligand that has only one lone pair
H2O
Cl-
NH3

Question 11

what is bidentate?

Answer 11

ligand that has 2 lone pairs
Ethane1,2diamine
ethandioate

Question 12

what is a multitdentate

Answer 12

ligands that has more than 2 lone pairs

EDTA(4-) can form 6 coordiante bonds with central metal ion

Question 13

what is the coordination number?

Answer 13

the number of coordiante bonds in the complex

Question 14

what is the complex shape based off

Answer 14

size of ligands

coordination number

Question 15

how many of each ligand can you fit around an ion?

Answer 15

NH3 and H2O 6
Cl- 4
ethane1,2diamine and ethanedioate 3

Question 16

what is the shape of coordination number 6?

Answer 16

octahedral with 90 degrees bond angle
Co(H2O)6(2+)
Co(NH3)6(2+)

Question 17

what are the shapes of coordination number 4?

Answer 17

tetrahedral bond angle of 109.5
square planar (cis platain) bond angle of 90

CuCl4(2-)
Pt(NH3Cl2)

Question 18

what is the shape of coordination number 2?

Answer 18

linear with bond angle 180

Ag(NH3)2(+)

Question 19

what shape is haem ?

Answer 19

octahedral

Question 20

how is oxygen transported with haemoglobin

Answer 20

at the lungs haemoglobin h2o ligand is replaced by o2
oxyhaemoglobin is carried to where it is required and released
this allows h2o to join back on

Question 21

why is carbon monoxide harmfulFeb

Answer 21

ligand forms strong bond with Fe which is not replaced by water leading to lack of oxygen

Question 22

what type of complex ions show optical isomerism?

Answer 22

octahedral complex with 3 bidentate ligands

ethane12diamine, ethandiaote

Question 23

what 2 type of complex ions show cis/trans isomerism

Answer 23

octahedral with 4 ligands of the same type and 2 different
trans= opposite each other cis=adjacent
cisplatain with 2 ligans same and 2 diffeerent
trans opposite cis = the same side

Question 24

what happens to ligands d orbital when they join the central ion?

Answer 24

the orbitals gain energy and an energy gap is created
when light energy is absorbed by these electrons it causes some to move from the ground state to the excited state
the energy from the light is ΔE

Question 25

what is ΔE based on?

Answer 25

the type of ligand the tcentral ion and its oxidation state the coordination njumber

Question 26

what is the formula to work out ΔE

Answer 26

``` ΔE (j)=hv h=planks constant j/s v=frequency of light absorbed hz ΔE (j)=hc/λ c=speed of light m/s λ= wavelength of light absorbed m ```

Question 27

describe how colours of transition metals are shown?

Answer 27

the larger ΔE the higher the frequency of the light absorbed any frequency not absorbed is reflected or transmitted this produces a complementary colour which is observed

Question 28

describe how calorimiter works

Answer 28

1) the calorimiter is set to 0 by measuring the absorbance of a blank sample usually solvent.white light is divided into monochromatic and hits the sample very little is absorbed and most travels through.This light that travels through can be measured by a detector and hence the absorption can be noted.

Question 29

describe 3 types of ligand substitutionnn reaction?

Answer 29

complete substituion Co(H2O)6(2+) +6(NH3) -> Co(NH3)6(2+) +6H2O pink->straw partial substituion Cu(H2O)6(2+) +4NH3 -> Cu(H2O)2(NH3)4(2+) +4H2O blue->dark blue shape change Co(H2O)6(2+) + 4Cl- -> Co(Cl4) (2-) + 6H2O pink ->blue octahedral -> tetrahedral

Question 30

why is a reaction that goes from a monodentate ligand complex to a multidentate ligand complex hard to reverse?

Answer 30

as their are more particles on the left hand side of the reaction their is a higher entropy making the reaction more likely to occur

Question 31

what are the different oxidation states of vanadium ions and its colours

Answer 31

V(2+) violet V(3+) green VO(2+) blue VO2(+) yellow vanadate (v)

Question 32

how is vanadium (v) reduced all the way to V(2+)

Answer 32

acidic zinc solutoin 2VO2(+) + zn + 4h->2VO(2+) +Zn(2+) + 2H2O yellow -> blue 2VO(2+) + zn + 4h ->2V(3+) + Zn(2+) + 2H2O blue -> green 2V(3+) + zn -> 2V(2+) + Zn(2+) green -> yellow

Question 33

why is ligands standard electrode potential not alaways accurate?

Answer 33

it is measured in an aqueous solution (surrounded by water molecules) however the ligand can form stronger bonds to the metal ion in patricular oxidation states

Question 34

how does ph affect redox potentials

Answer 34

the more acidic a solution the the larger the electrode potential making the ion more easily reduced

Question 35

how are redox titrations different to acid base titrations?

Answer 35

do not require an indidcator

Question 36

what are the 2 types of catalysts?

Answer 36

homeogeneous | heterogeneous

Question 37

drescibe homogeneous catalyst?

Answer 37

Catalyst in a different state to the reactant rely on large surface area to increase reaction rate

Question 38

describe heterogeneous catalsyt | ?

Answer 38

catalsyt in the same state | usually forms intermediates which can react to form product

Question 39

why are transition metals good cataylst

Answer 39

recieving and losing electrons in the d orbital speeds up reactions

Question 40

how is vanadium used to catalyse SO2->SO3

Answer 40

V2O5 + SO2-> V2SO4 + SO3 V2SO4 + 1/2O2 -> V2SO5

Question 41

what does heterogeneous catalyst poisoning mean?

Answer 41

When a heteregeneous catalyst active is blocked by impurities it causes it lose surface area hence reducing the reaction rate. To prevent the cataylst must be cleaned/replaced

Question 42

why are homogeneous catalyst energy profiles different?

Answer 42

the produce 2 activation energy bumps with the first for the intermediate compound and the 2nd to regenerate the catalyst overall reaction S2O8(2-)+I(-)->S2O4(-) + I2 intermediate S2O8(2-) + 2Fe(2+)->S2O4(-) + 2Fe(3+) catalyst reformed 2Fe(3+) + 2I(-) -> I2 + 2Fe(2+)

Question 43

what is autocatalysis ?

Answer 43

when the products acts acts as the catalyst overall reaction 2Mno4(-) + 16H(+) +5C2O4(2-)->2Mn(2+) + 8H2O + 10CO2 First reaction MnO4(-) + 8H(+) +4Mn(2+)->5MN(3+) + 4H2O Mn2+ REFORMED 2Mn(3+) + C2O4(2-) -> 2Mn(2+) + 2CO2

Question 44

Draw a diagram to show the apparatus that you would use to collect and measure the volume of the oxygen forme

Answer 44

stoppered flask connected with a gas sryinge

Question 45

The complex ion formed in aqueous solution between cobalt(II) ions and chloride ions is a different colour from the [Co(H2O)6] 2+ ion. Explain why these complex ions have different colour

Answer 45

the d orbitals splitting different light energy is absorbed causing electrons to be exited causing different wavelength/colour

Question 46

what are the colours of chromium?

Answer 46

Cr2O7(2-) orange | Cr3+ green