Metals

2.1 Reactivity Series

recall the reactivity series: potassium sodium calcium magnesium aluminium zinc iron [hydrogen] copper

Review the relative reactivity of metals. Discuss the ability of metals to compete for oxygen. Determine relative order of reactivity based on experimental results and then expand the series with other metals.

justify the positions of metals in the reactivity series by reference to their reactions with water, acids and aqueous solutions of salts where appropriate

Discuss the reactions which enable the metals to be put in an order of reactivity.

understand that reactions of metals with acids are particular examples of displacement reactions

Explain the meaning of the term 'displacement reaction'.

use the reactivity series to predict the outcome of reactions and predict the position in the reactivity series of unfamiliar metals from their reactions

write balanced and ionic equations to represent the reactions of metals in this section

Review writing balanced equations and ionic equations.

2.2 Variation in Reactivity in the Periodic Table

understand that the periodic table shows elements in order of increasing atomic number, arranged in rows (periods) so that elements with similar properties appear in the same vertical column (group)

Discuss the need to organise the elements to help understanding and rationalise data. Discuss the historical background. Discuss the terms used with respect to the periodic table: group, period.

recall the position of metals and non-metals in the periodic table and their characteristic physical properties

Discuss the positions of metals and non-metals in the Periodic Table

recall the positions of the alkali metals (Group 1), the halogens (Group 7), the noble gases (Group 0) and the transition metals in the periodic table

Discuss the names and positions of Groups 1, 7, 0 and the transition metals. Show samples of the elements of Groups 1, 7, 0 and the transition metals; discuss their chemical and physical behaviour, looking at their metallic and non-metallic properties. Discuss why the Group 1 elements are stored in oil.

understand the connection between the arrangement of outer electrons and the position of an element in the Periodic Table.

Remind pupils about electron arrangements. Draw attention to the number of electrons in the outer shell and the group number of the element.

understand that the reactions of elements depend upon the arrangement of electrons in their atoms

consider the elements of Period 3: sodium to argon of the Periodic Table. Discuss the results of the reactions and relate the behaviour of the elements to their atomic structures.

recall that there is a gradual change in the properties of the elements from the top to the bottom of each group

The reactions between the Group 1 metals and water may have been demonstrated earlier; the trend in chemical properties can be drawn from their observations. Pupils could be asked if the same trends would apply to the elements of Group 7; the reaction between the halogens and iron wool provides the answer.

2.3 Extraction of Metals

recall that metal ores are found in the Earth

Discuss with pupils where metals come from. Define the terms 'metal ore' and 'mineral'.

understand that the order of discovery and the uses of metals depend on their reactivity and ease of extraction

Remind pupils that Ag and Au occur naturally and have been used since 6000 BC. Brief discussion then place Bronze Age (Cu and Sn) before the Iron Age; mention can be made that Sn is below Fe in the reactivity series (Cu 4000 BC, Sn 1500 BC, Fe 500 BC). Aluminium should then be discussed - first used in 1900 AD.

recall that the way in which a particular metal is extracted from its ores is related to its reactivity (see also 'The reactivity series of metals').

Link this to the reactivity series and methods of extraction summarised (note: pupils are not expected to remember the dates and any relevant historical information would be given in a question linked to the idea of reactivities).

define reduction in terms of loss of oxygen and oxidation as the reverse process

Review previous knowledge of oxidation. Consider what happens to a Mg atom when it changes to MgO; hence oxidation as addition of oxygen; similarly the Cu atom changing to copper oxide. Explain reduction as the reverse process and hence as loss of oxygen.

define reduction in terms of loss of oxygen or gain of electrons and oxidation as the reverse process

Review previous knowledge of oxidation. Consider what happens to a Mg atom when it changes to a cation in MgO; hence oxidation as addition of oxygen or loss of electrons; similarly the Cu atom changing to the cation in copper oxide. Explain reduction as the reverse process and hence as loss of oxygen or gain of electrons.

understand that the extraction of metals involves reduction of their ores

Discuss the idea that many metals in ores are found as oxides or carbonates; removal of the oxygen (and hence reduction) should leave the metal. Relate back to the historical aspects of the extraction of metals (section 305) and introduce the copper ore, malachite, as a possible source of copper known to man centuries ago; discuss the ways in which the copper could have been obtained from the malachite.

recall that electrolysis is used to extract more reactive metals

Review the methods of extraction covered in previous sections. Remind pupils that Al was not extracted until 1900 when electricity was available; discuss which other metals would have to be extracted in this way.

describe the extraction of aluminium from purified bauxite including simple cell diagram, nature of electrolyte and electrodes and reactions

Relate the position of aluminium in the reactivity series to methods of extraction of other metals to establish the need for the use of electricity. Discuss the need for purified bauxite and for the use of cryolite.

understand why aluminium is less reactive than expected and appreciate how anodising is achieved and the change that takes place during the process

appreciate the need for alloying aluminium to increase its strength

understand the important uses of aluminium and its alloys

write balanced equations to describe and explain a wide range of reactions including those occurring in electrolytic cells

Discuss what happens at the electrodes and illustrate with reaction half-equations. Remind pupils that (in the electrolysis of Al₂O₃) the anode is made of C and discuss what happens to it during electrolysis.

recall that carbon and carbon monoxide can reduce the oxides of less reactive metals

Review the reactivity series and discuss the idea that the oxides of the less reactive metals are more easily reduced. Introduce the idea that carbon is easily oxidised to CO₂; discuss with the pupils the possible outcome of reacting metal oxides with carbon. Discuss with the pupils that, in a limited supply of air (O₂), C forms CO which is also used for reducing metal oxides.

describe the extraction of iron in the blast furnace, including outline diagram, raw materials, reactions and the formation and uses of slag

Discuss the importance of iron in today's world. Discuss the reactions taking place at various points in the blast furnace for: producing heat energy, producing CO, reducing the iron oxide using CO, production of slag. Discuss the uses of slag.

describe the extraction of iron in the blast furnace, including outline diagram, raw materials, reactions and the formation and uses of slag

explain the chemical reactions occurring in different parts of the blast furnace and the energy changes associated with them

understand that impure iron from the blast furnace and pure iron have very limited uses

describe the production of mild steel by lowering the carbon content in the impure iron using high pressure oxygen

understand the uses of mild steel

understand the uses of alloy steels such as stainless steel, titanium steel and manganese steel

Understand that processes involving the use of large amounts of electricity are relatively expensive

Review and summarise the processes of metal extraction.

Describe the purification of copper by electrolysis, including a simple diagram of the cell

Discuss the need for pure copper, for example for electrical wires. Review previous knowledge of electrolysis. Relate what the pupils have investigated to the purification of copper.

Relate the properties of metals to their uses in everyday life

2.4 Transition Metals

Recall that transition metal compounds are generally coloured

Make a display of a variety of coloured transition metal compounds and white/colourless non-transition metal compounds.

Recognise that iron and copper are transition metals

Discuss the reactions of metals pupils have met in the course. Discuss how they could investigate the physical and chemical properties of copper and iron.

Recall the use of transition metals and their compounds as catalysts

NB: This depends on the pupils having covered rates of reaction.

Discuss the meaning of the term 'catalyst'. Demonstrate the decomposition of H₂O₂ by heat, collecting and identifying the O₂ evolved. Discuss what could speed up the decomposition without increasing the energy input.

Relate the uses of iron and copper to their properties