© Boardworks Ltd 20071 of 35. 2 of 35© Boardworks Ltd 2007

© Boardworks Ltd 20071 of 35

2 of 35 © Boardworks Ltd 2007


Where are the transition metals?

The transition metals are the block of elements located between group 2 and group 3 of the periodic table.

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

?

Here, the word ‘transition’ is used to mean ‘in-between’.

group 2 group 3


What are the transition metals?


Why are they called the ‘typical metals’?

There are over 30 transition metals.

The transition metals are known as ‘typical’ metals. Why do you think this might be?

They include most of the metals we are familiar with and use everyday, such as iron, copper and gold.

However, there are many transition metals that are less familiar to us, because they are very rare or have few uses.



The transition metals are known as ‘typical’ metals because of their physical properties. They are:

What are the properties of the transition metals?

lustrous (bright and shiny).

high density.

good conductors of heat and electricity.

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

hard and strong.

malleable (can be bent and pressed into different shapes) and ductile (can be drawn into wires).


Transition metals and alkali metals

How do the transition metals compare with the alkali metals?


Comparing properties of different 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 there are more atoms of a transition metal than there are of an alkali metal.

have higher melting and boiling points – except mercury.

are harder and stronger. They cannot be cut with a knife.

Compared to the alkali metals, the transition metals:


Comparing densities of metals


Comparing melting points of metals


True or false?



How reactive are the transition metals?

The transition metals are much less reactive than the alkali metals.

They tend to react relatively slowly, for example with air, water and acid.

Copper does not react with water whereas the alkali metals, such as sodium, react vigorously.

Copper does not burn in air whereas the alkali metals, such as sodium, burn vigorously.


How reactive are the transition metals?

The general trend is for a decrease in reactivity from left to right across the periodic table. There are exceptions, such as zinc which is more reactive than expected.

Sc Ti V Cr Mn Fe Co Ni Cu Zn

decrease in reactivity

Another exception is iron, which does react quite readily with air and water causing rust.

Zinc is more reactive than expected.

What is the chemical name of rust?


What happens to iron when it rusts?

Rusting is an oxidation reaction between iron, oxygen and water, which leads to the formation of hydrated iron (III) oxide - the chemical name for rust.

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

wateroxygen hydrated iron (III) oxide (rust)

iron + +

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

Rusting is a type of corrosion.


Transition metal ions

When transition metals do react, they lose electrons, and so form positive ions.

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

However, most transition metals can form more than one type of ion, as they can lose different numbers of electrons, for example:

silver only forms Ag+ ions

zinc only forms Zn2+ ions.

iron can form both Fe2+ and Fe3+ ions.


Transition metal compounds

The number in brackets indicates how many electrons have been lost.

As most transition metals can form different ions, this means they can form multiple compounds.

Copper can form Cu+, which can make the red compound copper (I) oxide – Cu2O.

Copper can also form Cu2+, which can make the black compound copper (II) oxide – CuO.

For example:


Transition metal compounds and colour

Most transition metals form coloured compounds.

Copper (II) sulfate crystals (CuSO4.H2O) is blue – these can be turned white by heating the crystals to remove the water.

Iron (III) oxide (Fe2O3) is red/brown – when hydrated this is rust.

Iron (II) oxide (FeO2) is black.

For example:


Uses of coloured tm compounds

The coloured compounds of transition metals can also be used in many ways, for example:

as coloured glazes on pottery.

to colour paints

to colour stained glass windows

The colour of many gemstones comes from the presence of transition metal compounds. For example, the gemstone jade contains iron.


How are transition metal ions identified?

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

If transition metal ions are present, a metal hydroxide is formed. This is insoluble and so 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:


What is thermal decomposition?

Compounds of transition metals can be broken down into simpler substances by heating them.

For example, carbonates of transition metals are broken down into metal oxides and carbon dioxide when heated.

metal oxidemetal carbonate + carbon dioxideheat

How can the presence of carbon dioxide be tested?

This is called thermal decomposition.

The reactants and products are different colours.

The gas produced can be bubbled through limewater. If the gas is CO2, it will turn the limewater cloudy.


Thermal decomposition – equations

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

iron oxide

iron (II) carbonate + carbondioxide

heat

The thermal decomposition reaction of iron (II) carbonate is:

What is the reaction when copper (II) carbonate undergoes thermal decomposition?

+CuCO3 (s) CO2 (g)CuO (s)

copper oxide

copper (II) carbonate +carbon dioxide

heat


Thermal decomposition – activity


Transition metals – missing words



Spot the uses of the transition metals

How many everyday uses of transition metals can you see?


What are the uses of the transition metals?


Uses of transition metals – activity



Glossary (1/2)

alloy – A mixture of a metal and at least one other element.

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 reaction such as rusting.

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

ductile – The ability of metals to be drawn into wires.

lustrous – Bright and shiny.

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


Glossary (2/2)

precipitate – A solid that forms in a solution as a result of 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.


Anagrams


Properties of transition metals


Multiple-choice quiz

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© Boardworks Ltd 20071 of 35. 2 of 35© Boardworks Ltd 2007