23.1 General properties of transition metals

Question 1

Where do the transition metals element start and end

What elements does this cut out and why

Answer 1

. Range from titanium to copper

This cuts out scandium and zinc because transition metals need to have ions with a partially full d shell of electrons whereas these two don’t!

Eg zinc forms Zn2+ ion (3d10) in all its compounds
And scandium forms Sc3+ (3d0) in all its compounds

As a result they are d block elements but not transition metal elements

Question 2

Why are transition metals useful with the properties:

. Conductivity
. Appearance
. Melting and boiling points

Answer 2

. They are good conductors of heat and electricity

. They are hard, strong and shiny

. They have high melting and boiling points

These make them useful as they also have a low reactivity.

Question 3

What is transition metal Fe useful

Answer 3

Iron and its alloy steel can be used for vehicle bodies and to reinforce concrete

Question 4

How is copper used

Answer 4

. Water pipes

Question 5

How is titanium used

Answer 5

. Jet engine parts that must withstand high temperatures

Question 6

Why are transition metal elements similar

Answer 6

. In general there are two 4s electrons,
and as you go across the period, electrons are added to the 3d subshell

Question 7

What transition metal elements don’t fit the pattern

Answer 7

Copper and chromium because the d sub level is full (3d10) in copper and it is half full in chromium (3d5) and there is only one electron in the 4s outer level.

A half full d level makes the atoms more stable in the same way a full outer main level makes the noble gas atoms stable.

. It is 3d10 in copper because when the 3d sub shell has 9 electrons, it takes one from the 4s sub shell to get a full one.
The same happens for chromium when there are 4 3d electrons, so it takes one from the 4s shell so one electron can go in each of the 5 orbitals

Question 8

Give the electron configuration of V and then give it of
V2+

Why are the electrons lost from the 4s sub shell before the 3d

Answer 8

1s2 2s2 2p6 3s2 3p6 3d3 4s2

1s2 2s2 2p6 3s2 3p6 3d3

Because once the sub shells are full, the 4s sub shell has more energy than the 3d sub shell so the electrons can be lost from it first

Question 9

Electron configuration of the Cu element

Give it of Cu2+

Answer 9

1s2 2s2 2p6 3s2 3p6 3d10 4s1

1s2 2s2 2p6 3s2 3p6 3d9

Question 10

Electron configuration of Cr

Cr3+ ion

Answer 10

1s2 2s2 2p6 3s2 3p6 3d5 4s1

1s2 2s2 2p6 3s2 3p6 3d3

Question 11

What is the definition of a transition metal element

Answer 11

. An element that forms at least one stable ion with a partially full d shell of electrons

Question 12

What are the 4 main features of chemical properties of transition metals

Answer 12

1) Variable oxidation states:

2) Colour:

3) Catalysis:

4) Complex formation

Question 13

Describe the oxidation states of transition metals

Answer 13

Transition metals have more than one oxidation state in their compounds

eg Cu(i) or Cu(ii). So they can take part in many redox reactions

Question 14

Describe colour of transition metals

Answer 14

The majority of transition metals are coloured eg Cu2+ is blue

Question 15

Describe the use of transition metals as catalysts

Answer 15

. Catalysts affect the rate of reaction without being used up or chemically changed in the reaction themselves.

Many transition metals and their compounds show catalytic activity.

Eg Iron is the catalyst in the haber process
Vanadium oxide is the catalyst in the contact process
Manganese(IV) oxide in the decomposition of hydrogen peroxide.

Question 16

Describe use of transition metals in complex formation

Answer 16

. Transition metals form complex ions

. A complex ion is formed when a transition metal ion is surrounded by ions or other molecules, collectively called ligands which are bonded to it by co-ordinate or dative bonds

Eg [Cu(H2O)6]2+ is a complex ion formed when copper sulfate dissolves in water