Transition Metals (3.2.5) Flashcards

1
Q

What is a transition metal?

A

An element that has an incomplete d sub-shell in either its atoms or one of its common ions

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

Properties of transition metals

A
  • Variable oxidation states
  • Catalytic action
  • Coloured compounds
  • Formation of complexes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a ligand?

A

A particle with a lone pair of electrons that bonds to metals by a dative/co-ordinate bond

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

What is a complex?

A

A metal ion surrounded by co-ordinately bonded ligands

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

What is the co-ordination number?

A
  • The number of coordinate bonds from ligands to the metal ion
  • (Harpoons)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a Lewis base?

A

A lone pair donor (nucleophile)

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

What is a Lewis acid?

A

A lone pair acceptor (electrophile)

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

How many H2O ligands bond to a transition metal?

A

6

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

How many NH3 ligands bond to a transition metal?

A

6

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

How many Cl- ligands bond to a transition metal?

A

4

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

How many ligands can Ag bond to?

A

2 (always linear)

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

LEWIS BASE or LEWIS ACID

1) Ligands
2) Metal ion

A

1) Lewis Base –> donates a pair of electrons

2) Lewis Acid –> accepts lone pairs

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

What is the co-ordination number of a linear complex?

A

2

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

What is the co-ordination number of a square planar complex?

A

4

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

What is the co-ordination number of a tetrahedral complex?

A

4

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

What is the co-ordination number of an octahedral complex?

A

6

17
Q

Examples of linear complexes

A
  • Ag+ complexes

- e.g. [Ag(NH3)2]+ (Tollen’s reagent)

18
Q

Examples of square planar complexes

A
  • Pt 2+ & Ni 2+ complexes

- e.g. [PtCl4]2- (cisplatin)

19
Q

Examples of tetrahedral complexes

A
  • Larger ligands (too big to fit 6)
  • Cl-
  • e.g. [CuCl4]2-
20
Q

Examples of octahedral complexes

A
  • Most complexes with small ligands (so 6 can fit)
  • H2O, NH3 etc
  • e.g. [Cu(H2O)6]2+ (blue)
21
Q

What is a unidentate ligand?

A

A ligand that forms one co-ordinate bond to a metal ion

22
Q

Example of unidentate ligands

A

Cl-, OH-, CN-, H2O, NH3

23
Q

What is a bidentate ligand?

A

A ligand that forms two co-ordinate bonds to a metal ion

24
Q

Example of bidentate ligand

A

> 1,2-diaminoethane (en)

> ethanedioate ion (C2O4 2-)

25
Q

What is a multidentate ligand?

A

A ligand that forms more than two co-ordinate bonds to a metal ion

26
Q

Example of a multidentate ligand

A

> EDTA 4- (6 bonds, octopus)

> Porphyrin (4 bonds)

27
Q

What is Haemoglobin made up of?

A
  • Globular protein, made up of four Fe2- centres - each with a porphyrin ligand taking up four of the six co-ordination sites
  • One site is bonded to the structure
  • One site is left to take up oxygen as a ligand
  • Oxygen is not a great ligand, so can fall off easily to be used for respiration. Cyanide and (CN-) and carbon monoxide (CO) are better ligands, so stick to haemoglobin better than oxygen and prevent transport of oxygen (asphyxia)
28
Q

What shapes of molecules can display cis-trans isomerism?

A
  • Square Planar

- Octahedral

29
Q

Example of cis-trans isomerism?

A
  • Cisplatin (effective anti-cancer drug)

- Transplatin (no effect on cancer)

30
Q

What shape of molecule can optical isomerism display in?

A
  • Octahedral (only bidentate ligands)

- Mirror Plane reflection

31
Q

What is ligand substitution?

A

A reaction where one ligand is replaced by another

32
Q

What happens to the co-ordination number if H2O’s are replaced by NH3’s?

A
  • As NH3 and H2O are similar sizes, there is no change in co-ordination number
  • [Co(H2O)6]2+ + 6NH3 –> [Co(NH3)6]2+ + 6H2O
33
Q

What happens to the co-ordination number if the substitution is by a different sized ligand?

A
  • The co-ordination number may change
  • e.g., Cl- ligands are significantly bigger than H2O or NH3, so only 4 can fit around a central ion
  • Therefore the co-ord number changes (6–>4)
  • [Co(H2O)6]2+ + 4Cl- –> [CoCl4]2- + 6H2O
  • Charge stays same, overall 2-
34
Q

What is the Chelate effect?

A