3.4 Transition Metals (d Block)

Question 1

What is a transition metal ?

Answer 1

A transition metal is an element that possesses a partially filled d sub-shell as an atom or in its stable ions.

Question 2

What are the characteristics of a transition metal

Answer 2

variable oxidation states
complex ion formation
formation of coloured ions
catalytic activity.

Question 3

What are the two exceptions to the orbital shell

Answer 3

Chromium and copper fill their 3d subshell before 4s2

Question 4

Why can transition metals have various oxidation states?

Answer 4

Transition metals can have different oxidation states. This is because the energies of the 4s and 3d orbitals are very similar, so the energy required to remove any of these electrons (ionisation energy) is similar.

Question 5

Cobalt forms Co3+ as well as Co2+ ions. explain why transition metals such as cobalt form compounds with more than one oxidation state

Answer 5

3d and 4s electrons are involved in bonding
Ionisation energies needed to remove the 3d and 4s electrons and very similar.

Question 6

Define ligand

Answer 6

ligand is a small molecule or ion with a lone pair of electrons which can bond to a transition metal ion.

Question 7

What are monodentate and bidentate ligands

Answer 7

Ligands that have one atom which can bond to the metal ion eg water, ammonia, chlorine and cyanide

Ligands that have two atoms which can bond to the metal ion
Eg 1,2-diaminoethane.

Question 8

Colour and shape of fe2+ ligand

Answer 8

Octrahedral,
Pale green

Question 9

Shape and colour of fe3+ ligand

Answer 9

Octrahedral
Green

Question 10

Shape n colour of cr3+ ligand

Answer 10

Dark green
Octrahedral

Question 11

Shape and colour of co2+ ligand

Answer 11

Pink
Octrahedral

Question 12

Shape and colour of cu2+

Answer 12

Blue and Octrahedral

Question 13

Shape and colour of cu2+ with ammonia and water

Answer 13

Royal blue
Octrahedral

Question 14

Shape and colour of co2-

Answer 14

Blue
Tetrahedral

Question 15

Shape and colour of cu 2-

Answer 15

Yellow-green
Tetrahedral shape

Question 16

Degenerate meaning

Answer 16

Same energy

Question 17

Examples of transition metal as catalysts

Answer 17

iron in the Haber process
nickel to make margarine from the hydrogenation of vegetable oils
vanadium(V) oxide in the contact process

Question 18

Homogenous catalyst

Answer 18

Homogeneous catalysts are in the same physical state as the reactants

They work by using their variable oxidation states to oxidise/reduce a reactant, making it more reactive.

Question 19

Heterogenous catalyst

Answer 19

Heterogeneous catalysts are in a different physical state to the reactant

They work by having partially filled d orbitals. The catalyst provides a solid surface on which reactants can be adsorbed and brought closer together for more opportunity to react.

Question 20

Why are complex ions coloured

Answer 20

ligands cause d-orbitals to split into three lower and two higher energy levels (1)
electrons absorb energy and are promoted to a higher energy level (1)
colour seen is the colours not absorbed (1)