Transition Metals

Question 1

How are d-block transition metals defined?

Answer 1

Transition metallic elements that have an incomplete d subshell in at least one of their ions.

Question 2

What are ligands?

Answer 2

Ligands are electron donors and may be negative ions or molecules with non-bonding pairs of electrons.

Question 3

What is a dative covalent bond?

Answer 3

A covalent bond where both electrons of the shared pair come from the same atom.

Question 4

When is a ligand described as monodentate?

Answer 4

If it uses just one atom to bind to the central metal.

Question 5

What is the co-ordination number?

Answer 5

The total number of bonds from the ligands to the central transition metal atom/ion.

Question 6

How are water ligands written in a complex ion?

Answer 6

(OH₂)

Question 7

What is the name for the CN⁻ ligand in a complex ion?

Answer 7

Cyanido.

Question 8

What is the name for the C₂O₄²⁻ ligand in a complex ion?

Answer 8

Oxalato.

Question 9

What is the name for iron in a negative complex ion?

Answer 9

Ferrate.

Question 10

What is the name for copper in a negative complex ion?

Answer 10

Cuprate.

Question 11

What is the name for silver in a negative complex ion?

Answer 11

Argentate.

Question 12

What is the name for tin in a negative complex ion?

Answer 12

Stannate.

Question 13

What is the name for gold in a negative complex ion?

Answer 13

Aurate.

Question 14

What is the name for lead in a negative complex ion?

Answer 14

Plumbate.

Question 15

What is the theory that explains how colour arises in transition metal complexes?

Answer 15

Crystal field theory.

Question 16

Explain fully how colour arises in transition metal complexes.

Answer 16

The degenerate 3d orbitals of the transition metal atom are split by the action of ligands approaching and binding to it.
This means that they are no longer degenerate - 2 orbitals have a higher energy and 3 have a lower energy.
Electrons present in any of the lower energy d orbitals can absorb energy and get promoted to one of the higher energy d orbitals. This is known as a d-d transition.
If the energy absorbed is equal to a wavelength of light in the visible spectrum, the complementary colour will be transmitted.

Question 17

What does the colour of light absorbed by a transition metal complex depend upon?

Answer 17

The extent to which the d orbitals have been split.

Question 18

What 3 factors does the extent to which the d orbitals split depend upon?

Answer 18

The metal involved
The oxidation state of the metal
The nature of the ligand

Question 19

What is oxidation?

Answer 19

Oxidation is when there is an increase in oxidation number and a loss of electrons.

Question 20

What is reduction?

Answer 20

Reduction is when there is a decrease in oxidation number and a gain of electrons.

Question 21

What are compounds containing metals in high oxidation states often used as?

Answer 21

Oxidising agents.

Question 22

What are compounds containing metals in low oxidation states often used as?

Answer 22

Reducing agents.

Question 23

What are the 3 neutral ligands?

Answer 23

NH₃ (ammonia), CO (carbon monoxide, H₂O (water)

Question 24

What is the series that places ligands in order of their ability to split d orbitals?

Answer 24

Spectrochemical series.

Question 25

What can transition metals and their compounds act as?

Answer 25

Catalysts.

Question 26

What are heterogeneous catalysts?

Answer 26

Catalysts that are in a different state to the reactants.

Question 27

What are homogeneous catalysts?

Answer 27

Catalysts that are in the same state as the reactants.