Brainscape's Knowledge GenomeTM

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


See full index

Chemistry > Ch5.3 Transition elements > Flashcards

Ch5.3 Transition elements Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

Which 2 elements are exceptions to the Aufbau principle?

A

chromium and copper

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

How is chromium an exception to the Aufbau principle?

A
  • 3d and 4s orbitals all contain 1 unpaired e-
  • 1s2 2s2 2p6 3s2 3p6 4s1 3d5
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is copper an exception to the Aufbau principle?

A
  • 3d orbital is filled completely leaving 4s half-filled
  • 1s2 2s2 2p6 3s2 3p6 4s1 3d10
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which electrons are lost first when ions are formed of the transition elements and why?

A
  • 4s electrons are lost before the 3d electrons unlike in all other elements
  • this is because, once filled, the 4s electrons have a slightly higher energy than the 3d electrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define transition metal

A

a d block element that has an incomplete d-subshell as a stable ion

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

What are the physical properties of transition metals?

A
  • high density
  • high melting and boiling points
  • shiny in appearance (lustrous)
  • conduct electricity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the chemical properties of transition metals?

A
  • have variable oxidation states
  • transition metal compounds form coloured solutions in water
  • catalysts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Can transition metals form ions with more than one stable oxidation state?

A

Yes
- all of the transition metals in period 4 do this (Ti to Cu)

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

Which compounds containing transition metals can act as strong oxidising agents?

A
  • compounds containing a transition metal in a high oxidation state
    eg. potassium manganate (VII) KMnO4
    eg. potassium dichromate (VI)
    K2Cr2O7
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain what is meant by the statement: compounds of transition metals can undergo disproportionation

A
  • the transition metal species is both oxidised and reduced in the same reaction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Explain why transition metal compounds are often coloured

A
  • white light hits an object and part of the spectrum is absored by the object and the remaining is reflected which is the light we see
  • as light hits a transition metal ion, the electrons become excited (energised) and if there are some partially filled d sub-shells available, they can move up an energy level
  • as the electrons then drop back down, they release light energy which we see as colour

NOTE: a compound will only be coloured if the transition metal ion has partially filled d subshells

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

Define catalyst

A
  • a substance which speeds up a reaction by providing an alternative pathway with a lower activation energy and isn’t used up itself in the reaction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why are transition metals good catalysts?

A
  • reactants are ADsorbed to the surface of a transition metal where it may gain or lose electrons and form an intermediate allowing a pathway with a lower activation energy
  • the transition metals can vary in oxidation states and once the reaction has occurred, the products are DEsorbed and the transition metal remains unchanged
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the equation for hydrogen production?

A

Zn(s) + H2SO4(aq) –> ZnSO4(aq) + H2(g)

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

What is the catalyst for the reaction for hydrogen production?

A

CuSO4 or Cu2+ ion

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

What is the equation for the contact process?

A

2SO2 + O2 ⇌ 2SO3

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

What is the catalyst for the reaction of the contact process?

A

V2O5 or V5+ ion

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

What is the equation for oxygen production?

A

2H2O2 –> 2H20 + O2

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

What is the catalyst for the reaction for oxygen production?

A

MnO2 or Mn4+ ion

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

What is the equation for the Haber process?

A

N2 + 3H2 ⇌ 2NH3

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

What is the equation for the hydrogenation of ethene?

A

C2H4 + H2 –> C2H6

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

What is the catalyst for a catalytic converter?

A

Pt or Pd

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

What is the catalyst for vitamin B12?

A

Co

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

Define ligand

A

a molecule or ion that can donate a pair of electrons to the central transition metal ion to form a coordinate bond (dative covalent bond)

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

Define coordinate bond

A

a bond in which one of the bonded atoms provides both electrons for the covalent bond

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

State some features of ligands

A
  • all ligands have at least one lone pair of electrons
  • ligands can be neutral molecules or charged
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is a monodentate ligand?

A
  • a ligand that donates just one pair of electrons to the central metal ion to form one coordinate bond
  • eg. Cl- , OH- , CN- , NH3 , OH2 , SCN- (thiocyanate)
28
Q

What is a bidentate ligand?

A
  • a ligand that contains 2 atoms which donate a pair of electrons each to the central metal ion
  • 2 coordinate bonds are formed per ligand
29
Q

What is a multidentate ligand?

A
  • a ligand that can form several coordinate bonds
  • eg. EDTA 4- (ethylenediaminetetraacetic acid)
30
Q

Describe a linear complex ion giving its bond angles and occurrence

A
  • 2 bonding regions in straight line
  • angle 180 degrees
  • occurs in Ag+ complexes
31
Q

Describe a tetrahedral complex ion giving its bond angles and occurrence

A
  • 4 bonding regions spread as far apart as possible
  • angle 109.5 degrees
  • occurs with large ligands eg. Cl-
32
Q

Describe a square planar complex ion giving its bond angles and occurrence

A
  • 4 bonding regions spread as far apart as possible in a planar restriction
  • angle 90 degrees
  • occurs in Pt 2+ complexes
33
Q

Describe an octahedral complex ion giving its bond angles and occurrence

A
  • 6 bonding regions spread as far as possible
  • angle 90 degrees
  • most common occurrence
34
Q

What are the 2 types of stereoisomerism?

A
  • cis-trans / E-Z
  • optical isomerism
35
Q

What is stereoisomerism?

A

molecules or complexes with the same structural formula but with a different spatial arrangement of these atoms

36
Q

What is cis-platin and how does it work?

A
  • a very effective drug to fight cancer
  • it works by binding to DNA and stopping replication and cell division
37
Q

What is optical isomerism?

A
  • optical isomers are non-superimposable mirror images of each other
38
Q

What do ligand substitution reactions involve?

A
  • a ligand in a complex ion being removed and replaced by another ligand
  • common ligand substitution reactions involve the substitution of water molecules with another ligand
39
Q

[Cu(H2O)6]2+ + NH3 (dropwise)

equation, colours, type of reaction

A

[Cu(H2O)6]2+ + 2NH3 –> [Cu(H2O)4(OH)2] + 2NH4+

[Cu(H2O)6]2+ is pale blue solution

[Cu(H2O)4(OH)2] is pale blue precipitate

hydrolysis reaction

ammonia acts as a base pulling a proton off two of the water ligands

40
Q

[Cu(H2O)4(OH)2] + NH3 (excess after dropwise)

equation, colours, type of reaction

A

[Cu(H2O)4(OH)2] + 4NH3 –> [Cu(H2O)2(NH3)4]2+ + 2H2O + 2OH-

[Cu(H2O)4(OH)2] is a pale blue precipitate

[Cu(H2O)2(NH3)4]2+ is a deep blue solution

substitution reaction

adding NH3 in excess causes ligand exchange to occur

41
Q

[Cu(H2O)6]2+ + NH3 (excess straight away/overall reaction)

equation, colours, type of reaction

A

[Cu(H2O)6]2+ + 4NH3 ⇌ [Cu(H2O)2(NH3)4]2+ + 4H2O

[Cu(H2O)6]2+ is a pale blue solutiion

[Cu(H2O)2(NH3)4]2+ is a deep blue solution

substitution reaction

42
Q

[Cr(H2O)6]3+ + NH3 (dropwise)

equation, colours, type of reaction

A

[Cr(H2O)6]3+ + 3NH3 –> [Cr(H2O)3(OH)3] + 3NH4+

[Cr(H2O)6]3+ is a pale purple solution but can look green due to impurities

[Cr(H2O)3(OH)3] is a dark green precipitate

hydrolysis reaction

ammonia is acting as a base when it pulls protons from 3 of the water ligands

43
Q

[Cr(H2O)3(OH)3] + NH3 (excess after dropwise)

equation, colours, type of reaction

A

[Cr(H2O)3(OH)3] + 6NH3 –> [Cr(NH3)6]3+ + 3H2O + 3OH-

[Cr(H2O)3(OH)3] is a dark green precipitate

[Cr(NH3)6]3+ is a purple solution

substitution reaction
(more likely to occur with conc NH3)

44
Q

[Cr(H2O)6]3+ + 6NH3 (excess straight away/overall reaction)

equation, colours, type of reaction

A

[Cr(H2O)6]3+ + 6NH3 ⇌ [Cr(NH3)6]3+ + 6H2O

[Cr(H2O)6]3+ is a pale purple solution but can look green due to impurities

[Cr(NH3)6]3+ is a purple solution

substitution reaction

45
Q

[Cu(H2O)6]2+ + conc HCl

equation, colours, type of reaction

A

[Cu(H2O)6]2+ + 4Cl- ⇌ [CuCl4]2- + 6H2O

OR

[Cu(H2O)6]2+ + HCl ⇌ [CuCl4]2- + 6H2O + 4H+

[Cu(H2O)6]2+ is a pale blue solution

[CuCl4]2- is a yellow solution
(often looks green instead of yellow because there is a mix of the blue and yellow solutions present)

46
Q

[Cu(H2O)6]2+ + NaOH (dropwise vs excess)

equation, colours, type of reaction

A

dropwise full equation
[Cu(H2O)6]2+ + 2OH- –> [Cu(H2O)4(OH)2] +2H2O

dropwise simple equation
Cu2+ + 2OH- –> Cu(OH)2

excess: no further reaction

[Cu(H2O)6]2+ is a pale blue solution

[Cu(H2O)4(OH)2] / Cu(OH)2 is a blue gelatinous precipitate

hydrolysis reaction

47
Q

[Fe(H2O)6]2+ + NaOH (dropwise vs excess)

equation, colours, type of reaction

A

dropwise full equation [Fe(H2O)6]2+ + 2OH- –> [Fe(H2O)4(OH)2] + 2H2O

dropwise simple equation
Fe2+ + 2OH- –> Fe(OH)2

excess: no further reaction but precipitate darkens in time on the surface as it oxidises to [Fe(H2O)3(OH)3] (orange-brown precipitate)

[Fe(H2O)6]2+ is a pale green solution

[Fe(H2O)4(OH)2] / Fe(OH)2 is a dark green precipitate

hydrolysis reaction

48
Q

[Fe(H2O)6]2+ + NH3 (dropwise vs excess)

equation, colours, type of reaction

A

dropwise
[Fe(H2O)6]2+ + 2NH3 –> [Fe(H2O)4(OH)2] + 2NH4+

excess: no further reaction but the precipitate darkens with time on oxidation to [Fe(H2O)3(OH)3]

[Fe(H2O)6]2+ is a pale green solution

[Fe(H2O)4(OH)2] is a dark green precipitate

hydrolysis reaction

49
Q

[Fe(H2O)6]3+ + NaOH (dropwise vs excess)

equation, colours, type of reaction

A

dropwise full equation
[Fe(H2O)6]3+ + 3OH- –> [Fe(H2O)3(OH)3] + 3H2O

dropwise simple equation
Fe3+ + 3OH- –> Fe(OH)3

excess: no further reaction

[Fe(H2O)6]3+ is a pale yellow solution

[Fe(H2O)3(OH)3] is an orange-brown precipitate

hydrolysis reaction

50
Q

[Fe(H2O)6]3+ + NH3 (dropwise vs excess)

equation, colours, type of reaction

A

dropwise
[Fe(H2O)6]3+ + 3NH3 –> [Fe(H2O)3(OH)3] + 3NH4+

excess: no further reaction

[Fe(H2O)6]3+ is a pale yellow solution

[Fe(H2O)3(OH)3] is an orange-brown precipitate

hydrolysis reaction

51
Q

[Mn(H2O)6]2+ + NaOH (dropwise vs excess)

equation, colours, type of reaction

A

dropwise full equation
[Mn(H2O)6]2+ + 2OH- –> [Mn(H2O)4(OH)2] + 2H2O

dropwise simple equation
Mn2+ + 2OH- –> Mn(OH)2

excess:
no further reaction but the precipitate darkens over time as it oxidises:
4Mn(OH)2 + O2 –> 2Mn2O3 + H2O

[Mn(H2O)6]2+ is a very pale pink solution

[Mn(H2O)4(OH)2] is a brown precipitate

hydrolysis reaction

52
Q

[Mn(H2O)6]2+ + NH3 (dropwise vs excess)

equation, colours, type of reaction

A

dropwise
[Mn(H2O)6]2+ + 2NH3 –> [Mn(OH)2(H2O)4] + 2NH4+

excess:
no further reaction but the precipitate darkens over time as it oxidises:
4Mn(OH)2 + O2 –> 2Mn2O3 + H2O

[Mn(H2O)6]2+ is a very pale pink solution

[Mn(H2O)4(OH)2] is a brown precipitate

hydrolysis reaction

53
Q

[Cr(H2O)6]3+ + NaOH (dropwise)

equation, colours, type of reaction

A

[Cr(H2O)6]3+ + 3OH- –> [Cr(H2O)3(OH)3] + 3H2O

[Cr(H2O)6]3+ is a pale purple solution but can look green due to impurities

[Cr(H2O)3(OH)3] is a dark green precipitate

hydrolysis reaction

54
Q

[Cr(H2O)3(OH)3] + NaOH (excess after dropwise)

equation, colours, type of reaction

A

precipitate re-dissolves in excess hydroxide

[Cr(H2O)3(OH)3] + 3OH- –> [Cr(OH)6]3- + 3H2O

[Cr(H2O)3(OH)3] is a dark green precipitate

[Cr(OH)6]3- is a dark green solution

substitution reaction

55
Q

What is the test for ammonium ions?

A
  • add NaOH to NH4+ sample to make NH3 and H2O
  • NH3 will turn damp red litmus paper blue
56
Q

What is the test for carbonate ions?

A
  • add HCl to sample
    CO3 2- + 2H+ –> H2O + CO2

CO2 turns limewater cloudy when it’s bubbled through

57
Q

What is the test for sulphate ions?

A
  • add HCl followed by BaCl2
    Ba2+ + SO4 2- –> BaSO4

BaSO4 is a white precipitate

58
Q

What is the test for halide ions?

A
  • add nitric acid followed by silver nitrate

AgCl, AgBr or AgI formed

AgCl is white precipitate that dissolves in dilute or conc ammonia

AgBr is a cream precipitate that dissolves in just conc ammonia

AgI is a yellow precipitate that is insoluble in ammonia of any conc

59
Q

How does haemoglobin relate to ligand substituution?

A
  • haemoglobin is a complex protein of 4 polypeptide chains and each haemoglobin has 4 haem groups
  • each haem group has an Fe2+ ion at its centre, oxygen can reversibly bind to the Fe2+ ion which allows oxygen to be transported around the body
60
Q

Describe the stucture of the Fe2+ complex ion in haemoglobin

A
  • there are 4 coordinate bonds between the Fe2+ ion and the nitrogen atoms in the haem structure
  • a further coordinate bond is formed with globin protein
  • the final coordinate bond is formed with an O2 molecule which is then transported
61
Q

Describe and explain how CO is related to haemoglobin and ligand substitution

A
  • CO and O2 can both bind to haemoglobin at the same place
  • CO binds more strongly to the haemoglobin than O2
  • if CO and O2 are both present in the lungs then CO will bind over O2 so there is less haemoglobin for O2 to bind to
  • CO molecules can replace O2 molecules and they are both ligands so this is ligand substitution
  • reaction of binding isn’t reversible for CO
62
Q

What happens to the body if CO and O2 are both present in the lungs at the same time?

A
  • tissues are starved of O2 because it can’t be transported
63
Q

What symptoms can different concentrations of CO in the blood cause?

A
  • low concs: headaches, nausea and potential suffocation
  • high concs: fatal
64
Q

How is CO formed?

A
  • during incomplete combustion of carbon-containing fuels
  • burning tobacco also releases CO which is why long-term smokers become short of breath
65
Q

What are the physical properties of CO?

A
  • colourless
  • odourless
66
Q
A

Chemistry (17 decks)

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