© boardworks ltd 2005 1 of 35 ks4 chemistry transition metals

© Boardworks Ltd 20051 of 35

KS4 Chemistry

Transition Metals


Transition Metals

Chemical properties

Uses

Introducing transition metals

Summary activities

Physical properties

Contents


The transition metals

Transition metals are located in the periodic table between group 2 and group 3. ‘Transition’ means ‘in-between’.

H He

Rn

Xe

Kr

Ar

Ne

Ra Ac Rf Db Sg Bh Hs Mt Ds Rg ? ? ? ? ? ? ?

Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At

Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I

Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br

Mg Al Si P S Cl

Be B C N O F

Cs

Rb

K

Na

Li

Fr

32

Ac Rf Db Sg Bh Hs Mt Ds Rg ?

La Hf Ta W Re Os Ir Pt Au Hg

Y Zr Nb Mo Tc Ru Rh Pd Ag Cd

Sc Ti V Cr Mn Fe Co Ni Cu Zn

transition metals


Common transition metals

There are over 30 transition metals, but many are rare and have few uses. What are some of the most important and well-known transition metals?

nickel

copper silver platinum gold

ironchromiumtitanium


Transition metal ions

All transition metals lose electrons when they react, and so form positive ions.

silver only forms Ag+ ions;

zinc only forms Zn2+ ions.

Cu+ copper (I) oxide – Cu2O

Cu2+ copper (II) oxide – CuOcopper

ironFe2+ iron (II) chloride – FeCl2Fe3+ iron (III) chloride – FeCl3

Metal Ion Example of compound

However, most transition metals can form more than one type of ion. They have variable valency. For example:

Some transition metals only make one type of ion, for example:


Transition Metals

Chemical properties

Uses


Summary activities

Physical properties

Contents Contents


The transition metals are often referred to as ‘typical’ metals because they have properties that most people associate with ‘common’ metals.

General properties

are hard, strong and have a high density;

are malleable and ductile;

have high melting and boiling points (except mercury, which is liquid at room temperature);

Transition metals:

are good conductors of heat and electricity.

are lustrous;


Density of transition metals


Melting point of transition metals


Comparison with alkali metals

How do the properties of transition metals compare with those of alkali metals?

are more dense – this means that, in a fixed volume of metal (e.g. 1 cm3), there are more atoms of a transition metal than of an alkali metal;

have higher melting and boiling points – except mercury;

are harder and stronger – they are not brittle and cannot be cut with a knife.

Transition metals:


True or false?


Transition Metals

Chemical properties

Uses


Summary activities

Physical properties

Contents


Reactivity of transition metals

Transition metals are less reactive than alkali metals.They tend to react relatively slowly, for example with airand water (except iron) and acid.

The general trend is for reduced reactivity across periods. There are exceptions, such as zinc being more reactive than might be expected.

Sc Ti V Cr Mn Fe Co Ni Cu Zn

decrease in reactivity


Rusting

Rusting is an oxidation reaction between iron, oxygen and water. It is a type of corrosion.

What are the word and chemical equations for the formation of rust?

wateroxygenhydrated iron (III) oxide (rust)

iron + +

4Fe (s) 2H2O (g) 2Fe2O3.H2O+ 3O2 (g)+


Transition metals and colour

How do transition metals compare to alkali metals?


Colour and transition metals

Most transition metals form coloured compounds.

copper (II) compounds are blue

iron (II) compounds are usually green

iron (III) compounds are usually orange/brown

e.g. copper (II) sulfate (CuSO4.H2O) – these can be turned white by heating the crystals to remove the water.

e.g. iron (II) chloride (FeCl2)

e.g. iron (III) oxide (Fe2O3) – when hydrated this is rust

For example:


Uses of coloured compounds

Coloured compounds of transition metals are used in many ways. For example:

glazes on pottery

paints

stained glass windows


Thermal decomposition

Compounds of transition metals can be broken down into simpler substances by heating them. This is called thermal decomposition.

For example, carbonates of transition metals are broken down into metal oxides and carbon dioxide when heated. The reactants and products are different colours.

+FeCO3 (s) CO2 (g)FeO (s)

iron oxideiron (II)carbonate

+ carbon dioxideheat

How can the presence of carbon dioxide be tested?


Thermal decomposition equations


Identifying transition metal ions

The presence of transition metal ions in a solution can be tested by adding sodium hydroxide solution.

If they are present, a metal hydroxide is formed. This is insoluble so it appears as a solid called a precipitate.

Cu2+ ions produce a blue precipitate of Cu(OH)2

Fe2+ ions produce a grey/green precipitate of Fe(OH)2

Fe3+ ions produce an orange/brown precipitate of Fe(OH)3

Different metal ions produce different coloured precipitates.

For example:


Transition Metals

Chemical properties

Uses


Summary activities

Physical properties

Contents


Uses of iron

Transition metals have many uses, and these are directly related to their physical properties.

Iron is hard, strong, abundant and not too expensive.

It is therefore used in construction and engineering, but it is usually turned into steel first.


Uses of titanium

Alloys of titanium are used in the aerospace industry, and in artificial joints, such as hip ball and sockets.

Titanium is as strong as steel but much lighter, and is very resistant to corrosion.

Titanium dioxide is a brilliantly white compound used in paints, plastics, paper and toothpaste.


Uses of copper

Copper is used in wires and cables because of its good electrical conductivity, and used in plumbing because it is unreactive with water.

Copper is also used as a roofing material. The copper reacts slowly with gases and water in the air to create a thin green layer of copper compounds. This prevents the rest of the copper from reacting.


Alloys

Transition metals are often mixed with other metals ornon-metals to form alloys. This changes the property of the metal so it is better suited for a particular purpose.

Steel is an alloy of iron and other elements, such as carbon, nickel, manganese and chromium. There are many different types of steel, each with different properties.

Brass is an alloy of 70% copper and 30% zinc.

Bronze is an alloy of 90% copper and 10% tin.

Cupronickel is an alloy of 75% copper and 25% nickel – it is used in ‘silver’ coins.


Catalysts

Many transition metals and their compounds are used as catalysts.

A catalyst is a substance that speeds up a chemical reaction without being used up.

Catalysts are very important because they can save time, energy and money.

Nickel is a catalyst in the production of margarine (hydrogenation of vegetable oils).

Iron is a catalyst in the production of ammonia from nitrogen and hydrogen (the Haber process).


Catalysts – more examples

Platinum is a catalyst in catalytic converters to reduce levels of polluting gases. It speeds up the conversion of carbon monoxide and nitrogen oxide to carbon dioxide and nitrogen.

Titanium is a catalyst in the production of plastics.

What are other examples of transition metal catalysts?


Pairing metals with their uses


Transition Metals

Chemical properties

Uses


Summary activities

Physical properties

Contents


Glossary (part 1)

alloy – A material containing two or more metals, or a metal and a non-metal.

catalyst – A substance that increases the speed of a chemical reaction without being used up.

corrosion – Damage to a metal caused by a chemical or electrochemical reaction such as rusting.

density – A measure of mass in a given volume. Often expressed in g/dm3.

ductile – Capable of being drawn out into a wire.

lustrous – Bright and shiny.


Glossary (part 2)

malleable – Capable of being bent and pressed into a different shape.

precipitate – A solid that forms in a solution by a physical or chemical reaction.

thermal decomposition – The process by which a substance is broken down into two or more products by heating it.

transition metal – An element located in the block between groups 2 and 3 of the periodic table.

valency – The number of electrons an atom must gain or lose to obtain a full outer shell.


Anagrams


Reactivity and compounds


Properties of transition metals


Multiple-choice quiz

© boardworks ltd 2005 1 of 35 ks4 chemistry transition metals

Documents

common transition metals

wellknown transition

alkali metals

common metals

typical metals

transition metal ions

lustrous slide

general properties