Transition metals

Question 1

TM & d block elements?

Answer 1

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

Question 2

d block elements with a strange electron arrrangement?

Answer 2

Cr and Cu

Question 3

Cr electron arrangement ?

Answer 3

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

Question 4

Cu electron arrangement?

Answer 4

[Ar] 4s13d10

Question 5

Why does Cr have this arrangement?

Answer 5

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

Question 6

Why does Cu have this arrangement?

Answer 6

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

Question 7

when d block elements form ions which electrons are lost?

Answer 7

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

Question 8

first row d block elements that are not TM?

Answer 8

Scandium and zinc

Question 9

what is a TM?

Answer 9

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

Question 10

Sc ion always has an ox no of

Answer 10

+3

Question 11

Zn ion always has an ox number of

Answer 11

+2

Question 12

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

Answer 12

2 4s e- lost

Question 13

Cu (s) colour?

Answer 13

red/ brown solid

Question 14

KMnO4 colour and use?

Answer 14

• potassium manganate (VII)
• purple
• redox titrations

Question 15

CuSO4 colour and use?

Answer 15

• blue
• crystal growing
• testing for amines

Question 16

Na2Cr2O7 colour and use?

Answer 16

• orange

* oxidation of primary and secondary alcohols

Question 17

AgNO3 colour and use?

Answer 17

• colourless

* testing for halide ions

Question 18

FeBr3 colour and use?

Answer 18

• yellow

* halogen carrier

Question 19

TM general?

Answer 19

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

Question 20

BZ y axis?

Answer 20

no. of particles

Question 21

Ni as a catalyst?

Answer 21

• heterogeneous
• hydrogenation of alkenes
• producing margarine

Question 22

MnO2 as a catalyst?

Answer 22

• heterogeneous

* decomposition of H2O2 into H2O and O2

Question 23

Fe as a catalyst?

Answer 23

• hetero
• haber process
• producing NH3

Question 24

Vanadium pentoxide, V2O5 as a catalyst?

Answer 24

• hetero
• contact process - SO2 + 1/2O2 ➡ SO3
• producing sulphuric acid

Question 25

Cu as a catalyst?

Answer 25

• hetero
• oxidation of ethanol to form ethanal
• CH3CH2OH ➡ CH3CHO + 2H+ + 2e-
• Cu2+ + 2e- ➡ Cu(s)

Question 26

unusual for het to be

Answer 26

redox

Question 27

Co2+ as catalyst?

Answer 27

• homogeneous
• sodium potassium tartrate and H2O2
• produces CO2

Question 28

Fe2+ as a catalyst?

Answer 28

• homogeneous catalyst
• iodide and peroxodisulphate ions
• produces iodine

Question 29

Heterogenous catalysis

Answer 29

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

Question 30

heterogeneous catalysis is when

Answer 30

• catalyst and reactants in diff states

* TM can act as het catalysts bc empty d orbitals so can accept LP of e-

Question 31

TM have a vacant ?

Answer 31

d orbitals so lone pairs can be donated to the TM

Question 32

TM form

Answer 32

gelatinous precipitates

Question 33

homogeneous catalysis?

Answer 33

TM can easily change ox state - can exist in diff oxidation states

Question 34

Homogeneous catalysis equations?

Answer 34

• break equation down into oxidation and reduction equations
• oxidise/ reduce catalyst
• if O, goes w reduction equation
• do the opp
• pair again

Question 35

what other impact could a catalyst have?

Answer 35

• w a catalyst, may have a higher cell potential than uncatalysed, more likely to occur

Question 36

molecular ion?

Answer 36

ion w covalent bond inside, is charged

Question 37

dative covalent bond?

Answer 37

lone pair is donated by 1 atom - lone pair needed and empty orbital needed

Question 38

Complex ions involve

Answer 38

DCB and ligands

Question 39

ligands?

Answer 39

• 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

Question 40

lone pairs in ligand determines?

Answer 40

how many bonds ligands can form

Question 41

bidentate ligands have ? lone pairs

Answer 41

2

Question 42

e.g. of hexadentate ligand?

Answer 42

EDTA4-

Question 43

what is the co-ordination number?

Answer 43

number of dative covalent bonds to TM ion. CN usually 6, octahedral shape

Question 44

when is the CN 4?

Answer 44

• When halide ions are the ligand, tetrahedral shape

* G10 metals, square planar shape

Question 45

when is the CN 2?

Answer 45

• Ag

* Linear

Question 46

ligand substitution?

Answer 46

a ligand in a complex ion can be substituted by another ligand. The replacement ligand forms a more stable complex ion

Question 47

monodentate is the ?

Answer 47

easiest to remove in substitution. Hexadentate are the hardest bc wraps itself around TM

Question 48

when forming precipitate?

Answer 48

can use ion(aq) but when forming complex ion must write as [ion(water)6}charge

Question 49

same result after adding few drops NaOH and ?

Answer 49

a few drops of aq ammonia - prec forms

Question 50

only ? changes when excess NaOH is added?

Answer 50

Cr3+. Green solution forms, precipitate dissolves

Question 51

why do precipitates disappear when acid is added?

Answer 51

bases so react w acid to form, salt and water

Question 52

Cr3+ reaction?

Answer 52

• when NaOH added: green gel prep forms
• excess: clear green solution - [Cr(OH)6]3- forms
• w acid: reaction reversed - Cr(OH)3 forms

Question 53

darkening on surface is due to

Answer 53

oxidation

Question 54

Homogeneous catalysis?

Answer 54

• in solution