Transition Metals

Question 1

Give the definition of a transition metal

Answer 1

a metal which forms at least one stable ion with a partially filled d sub-shell

Question 2

List the properties/features of transition metals

Answer 2

1. Form complexes
2. Form coloured ions
3. Act as catalysts/ have catalytic properties
4. Variable oxidation states

Question 3

Define ‘co-ordinate bond’

Answer 3

Shared pair of electrons which have both come from the same atom

Question 4

Define ‘Ligand’

Answer 4

ion or molecule with a lone pair of electrons that can form a co-ordinate bond with a transition metal

Question 5

Define ‘Bidentate ligand’

Answer 5

Compound that has 2 separate atoms that each donate 2 electron pairs to the central position ion in a complex

Question 6

Define ‘coordination number’

Answer 6

Number of coordinate bonds a transition metal ion forms

Question 7

Define ‘complex ion’

Answer 7

A central atom or ion surrounded by ligands, linked by coordinate bods

Question 8

What are monodentate ligands

Answer 8

each ligand forms 1 coordinate bond

Question 9

what are bidentate ligands

Answer 9

each ligand forms 2 coordinate bonds

Question 10

what are multidentate ligands

Answer 10

each ligand forms more than 2 coordinate bonds

Question 11

Name 4 monodentate ligands

Answer 11

water - H2O
Ammonia - NH3
Chloride - Cl-
Cyanide - CN-

Question 12

Name 2 bidentate ligands

Answer 12

1,2-diaminoethane - H2NCH2CH2NH2
Ethanedioate ion - C2O4^2-

Question 13

What four shapes do transition metal complexes form?

Answer 13

Octahedral
Tetrahedral
Square Planar
Linear

Question 14

give the shape of [Cu(H2O)6]^2+

Answer 14

octahedral

Question 15

give the shape of [Pt(NH3)2(Cl)2]

Answer 15

Square planar

Question 16

Give the shape of [Ag(NH3)2]+

Answer 16

linear

Question 17

What is the only transition metal that can form a linear complex?

Answer 17

Silver (Ag)

Question 18

Give the structural formula of a Copper (II) Hexa Aqua Ion

Answer 18

[Cu(H2O)6]^2+

Question 19

Give the structural formula of a Cobalt (II) Chloride ion

Answer 19

[CoCl4]^2-

Question 20

Give the structural formula of a Nickel (II) Tetra Cyano Ion

Answer 20

[Ni(CN)4]^2-

Question 21

Give the structural formula for Silver (I) Ammonia Ion

Answer 21

[Ag(NH3)2]+

Question 22

How many coordinate bonds does EDTA^4- form, and where does each one come from?

Answer 22

6
2 bonds from the N atoms, 4 bonds from the O- atoms

Question 23

What shape does an EDTA4- Ligand occupy, when it coordinates to a transition metal?

Answer 23

octahedral

Question 24

Define ‘stereoisomers’

Answer 24

same structural formula
different arrangement of atoms in space

Question 25

If two of the same ligands are arranged opposite one another this shows ________ isomerism

Answer 25

trans

Question 26

If two of the same ligands are arranged next to each other this shows ________ isomerism

Answer 26

cis

Question 27

Which kind of complexes show optical isomerism?

Answer 27

complexes with AT LEAST TWO bidentate ligands Structure has to be CIS

Question 28

Give the structural formula of Cisplatin

Answer 28

Cis [PtCl2(NH3)2]

Question 29

Give a use for cisplatin

Answer 29

binds to DNA in cancer cells and stops cell replication

Question 30

What is a ligand substitution reaction?

Answer 30

Occurs when the ligand attached to a transition metal is replaces by an alternative ligand

Question 31

Why do chloro complexes tend to be tetrahedral?

Answer 31

Chloride ligand is too big to fit any more than 4 Cl- ligands around the metal ion

Question 32

What is the chelate effect?

Answer 32

When a monodentate ligand is substituted by a bidentate or multidentae ligand, resulting in an increase in entropy/disorder

Question 33

[Cu(NH3)6]2+ + 2H2NCH2CH2NH2 --> [Cu(H2NCH2CH2NH2)3]2+ + 6H2O Explain why this reaction is feasible

Answer 33

Enthalpy change is 0 Because the same number of Cu-N bonds are broken and formed 4 molecules produce 7 molecules Increase in disorder Large increase in entropy Gibbs free energy will be negative

Question 34

How does O2 travel through the blood?

Answer 34

O2 forms a coordinate bond to Fe2+ in haemoglobin enabling oxygen to be transported in the blood

Question 35

Why is CO toxic?

Answer 35

CO bonds more strongly to the Fe2+ in haemoglobin This prevents O2 from bonding to the Fe2+, causing suffocation Haemoglobin can no longer transport oxygen around the body