Chapter Notes: Metals

 Page 1


Behaviour of metals
? Physical properties of metals
? Shiny
? Good conductors of heat and electricity
? High density
? Malleable and ductile
? Usually solid at room temperature
? Sonorous (makes bell-like sounds when struck)
Chemical properties of metals
? The chemistry of metals is studied by analysis their reactions with water, dilute acid and oxygen
? Based on those reactions, a reactivity series of metals can be produced
? Reactivity with water
? Some metals react with water, either warm or cold or with steam
? Metals that react with cold water form a metal hydroxide and hydrogen gas
? For example, Ca + 2H2O ? Ca(OH)2 + H2
? Metals reacting with steam form metal oxide and hydrogen gas
? For example, Zn + H2O ? ZnO + H2
? Reactivity with acids
? Most metals react with dilute acids such as HCl
? When acids and metals react, the hydrogen atom in the acid is replace by the metal atom to
produce a salt and hydrogen gas
? For example, Fe + 2HCl ? FeCl2 + H2
? Reactivity with oxygen
? Unreactive metals such as gold and copper do not react with acids
? Some reactive metals such as alkali metals react with oxygen
? Copper and iron can also react with oxygen although much more slowly
? When metals react with oxygen, a metal oxide is formed for example copper
? For example, 2Cu + O2 ? 2CuO
? Alloys
? An alloy is a mixture of 2 or more metals or a metal and a nonmetal
? Alloys often have properties that can be very difficult to the metals they contain, for example
they can have more strength, hardness or resistance to corrosion or extreme temperatures
? Alloys contain atoms of different sizes, which distorts the normally regular arrangements of
atoms in metals
? This makes it more difficult for the laters to slide over each other, so alloys are usually much
harder than the pure metal
? Common alloys
? Brass is an alloy of copper and zinc and is much stronger than either metal
? Alloys of iron with tungsten are extremely hard and resistant to high temperatures
? Alloys of iron mixed with chromium or nickel are resistant to corrosion
Page 2


Behaviour of metals
? Physical properties of metals
? Shiny
? Good conductors of heat and electricity
? High density
? Malleable and ductile
? Usually solid at room temperature
? Sonorous (makes bell-like sounds when struck)
Chemical properties of metals
? The chemistry of metals is studied by analysis their reactions with water, dilute acid and oxygen
? Based on those reactions, a reactivity series of metals can be produced
? Reactivity with water
? Some metals react with water, either warm or cold or with steam
? Metals that react with cold water form a metal hydroxide and hydrogen gas
? For example, Ca + 2H2O ? Ca(OH)2 + H2
? Metals reacting with steam form metal oxide and hydrogen gas
? For example, Zn + H2O ? ZnO + H2
? Reactivity with acids
? Most metals react with dilute acids such as HCl
? When acids and metals react, the hydrogen atom in the acid is replace by the metal atom to
produce a salt and hydrogen gas
? For example, Fe + 2HCl ? FeCl2 + H2
? Reactivity with oxygen
? Unreactive metals such as gold and copper do not react with acids
? Some reactive metals such as alkali metals react with oxygen
? Copper and iron can also react with oxygen although much more slowly
? When metals react with oxygen, a metal oxide is formed for example copper
? For example, 2Cu + O2 ? 2CuO
? Alloys
? An alloy is a mixture of 2 or more metals or a metal and a nonmetal
? Alloys often have properties that can be very difficult to the metals they contain, for example
they can have more strength, hardness or resistance to corrosion or extreme temperatures
? Alloys contain atoms of different sizes, which distorts the normally regular arrangements of
atoms in metals
? This makes it more difficult for the laters to slide over each other, so alloys are usually much
harder than the pure metal
? Common alloys
? Brass is an alloy of copper and zinc and is much stronger than either metal
? Alloys of iron with tungsten are extremely hard and resistant to high temperatures
? Alloys of iron mixed with chromium or nickel are resistant to corrosion
? Aluminium is mixed with copper, manganese and silicon for aircraft body production as the alloy
is stronger but still has a low density
? Reactivity series
? The chemistry of the metals is studied by analyzing their reaction with water dilute acid and
oxygen
? Based on these reaction a reactivity series of metals can be produced
? The series can be used to place a group if metals in order of reactivity based on the observation
of their reactions with water, acid and oxygen
? Reactivity series
? Potassium , sodium , lithium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead,
hydrogen, copper, silver gold and platinum
? Reactions with aqueous ions and oxides
? The reactivity of metals increases going up the reactivity series
? This means that a more reactive metal can displace a less reactive metal from its oxide by
heating
? As magnesium is above copper in the reactivity series, magnesium is more reactive so can
displace copper
? CuO + Mg ? Cu + MgO
Page 3


Behaviour of metals
? Physical properties of metals
? Shiny
? Good conductors of heat and electricity
? High density
? Malleable and ductile
? Usually solid at room temperature
? Sonorous (makes bell-like sounds when struck)
Chemical properties of metals
? The chemistry of metals is studied by analysis their reactions with water, dilute acid and oxygen
? Based on those reactions, a reactivity series of metals can be produced
? Reactivity with water
? Some metals react with water, either warm or cold or with steam
? Metals that react with cold water form a metal hydroxide and hydrogen gas
? For example, Ca + 2H2O ? Ca(OH)2 + H2
? Metals reacting with steam form metal oxide and hydrogen gas
? For example, Zn + H2O ? ZnO + H2
? Reactivity with acids
? Most metals react with dilute acids such as HCl
? When acids and metals react, the hydrogen atom in the acid is replace by the metal atom to
produce a salt and hydrogen gas
? For example, Fe + 2HCl ? FeCl2 + H2
? Reactivity with oxygen
? Unreactive metals such as gold and copper do not react with acids
? Some reactive metals such as alkali metals react with oxygen
? Copper and iron can also react with oxygen although much more slowly
? When metals react with oxygen, a metal oxide is formed for example copper
? For example, 2Cu + O2 ? 2CuO
? Alloys
? An alloy is a mixture of 2 or more metals or a metal and a nonmetal
? Alloys often have properties that can be very difficult to the metals they contain, for example
they can have more strength, hardness or resistance to corrosion or extreme temperatures
? Alloys contain atoms of different sizes, which distorts the normally regular arrangements of
atoms in metals
? This makes it more difficult for the laters to slide over each other, so alloys are usually much
harder than the pure metal
? Common alloys
? Brass is an alloy of copper and zinc and is much stronger than either metal
? Alloys of iron with tungsten are extremely hard and resistant to high temperatures
? Alloys of iron mixed with chromium or nickel are resistant to corrosion
? Aluminium is mixed with copper, manganese and silicon for aircraft body production as the alloy
is stronger but still has a low density
? Reactivity series
? The chemistry of the metals is studied by analyzing their reaction with water dilute acid and
oxygen
? Based on these reaction a reactivity series of metals can be produced
? The series can be used to place a group if metals in order of reactivity based on the observation
of their reactions with water, acid and oxygen
? Reactivity series
? Potassium , sodium , lithium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead,
hydrogen, copper, silver gold and platinum
? Reactions with aqueous ions and oxides
? The reactivity of metals increases going up the reactivity series
? This means that a more reactive metal can displace a less reactive metal from its oxide by
heating
? As magnesium is above copper in the reactivity series, magnesium is more reactive so can
displace copper
? CuO + Mg ? Cu + MgO
? Displacement reactions between metals and aqueous solutions of metal salts
? Any metal will displace another metal that is below it in the reactivity series
? This is because more reactive metals lose electrons and form ions more readily than less
reactive metals making them better reducing agents.
? The less reactive metal is a better electron acceptor than the more reactive metal thus the less
reactive metal is reduced
? Zn + CuSO4 (aq) ? ZnSO4 (aq) + Cu
? Thermal decomposition reactions
? Compounds decompose or breakdown when they are heated to sufficiently high temperatures
? CaCO3 ? CaO + CO2
? Thermal decomposition of metal hydroxides
? Most metal hydroxides undergo thermal decomposition
? Water and the corresponding metal oxide are products formed
? Zn(OH)2  ? ZnO + H2O
? Thermal decomposition of metal carbonates
? The metal oxide and carbon dioxide are the products formed
? MgCO3 ? MgO + CO2
? Group 1 carbonates do not decompose when heated due to high thermal stability
? Thermal decomposition of metal nitrates
? Group 1 nitrates decompose forming the metal nitrite and oxygen
? 2NaNO3 ? 2NaNO2 + O2
? Other metal nitrates decompose to form metal oxide, nitrogen dioxide and oxygen
? 2Cu(NO3)2 ? 2CuO + 4NO2 + O2
? Aluminium although placed high in reactivity series does not react with oxygen because the surface of
aluminium reacts with oxygen in air to form a protective coating of aluminium oxide
? It is tough, unreactive and corrosion resistant therefore prevents aluminium from reacting with water
Page 4


Behaviour of metals
? Physical properties of metals
? Shiny
? Good conductors of heat and electricity
? High density
? Malleable and ductile
? Usually solid at room temperature
? Sonorous (makes bell-like sounds when struck)
Chemical properties of metals
? The chemistry of metals is studied by analysis their reactions with water, dilute acid and oxygen
? Based on those reactions, a reactivity series of metals can be produced
? Reactivity with water
? Some metals react with water, either warm or cold or with steam
? Metals that react with cold water form a metal hydroxide and hydrogen gas
? For example, Ca + 2H2O ? Ca(OH)2 + H2
? Metals reacting with steam form metal oxide and hydrogen gas
? For example, Zn + H2O ? ZnO + H2
? Reactivity with acids
? Most metals react with dilute acids such as HCl
? When acids and metals react, the hydrogen atom in the acid is replace by the metal atom to
produce a salt and hydrogen gas
? For example, Fe + 2HCl ? FeCl2 + H2
? Reactivity with oxygen
? Unreactive metals such as gold and copper do not react with acids
? Some reactive metals such as alkali metals react with oxygen
? Copper and iron can also react with oxygen although much more slowly
? When metals react with oxygen, a metal oxide is formed for example copper
? For example, 2Cu + O2 ? 2CuO
? Alloys
? An alloy is a mixture of 2 or more metals or a metal and a nonmetal
? Alloys often have properties that can be very difficult to the metals they contain, for example
they can have more strength, hardness or resistance to corrosion or extreme temperatures
? Alloys contain atoms of different sizes, which distorts the normally regular arrangements of
atoms in metals
? This makes it more difficult for the laters to slide over each other, so alloys are usually much
harder than the pure metal
? Common alloys
? Brass is an alloy of copper and zinc and is much stronger than either metal
? Alloys of iron with tungsten are extremely hard and resistant to high temperatures
? Alloys of iron mixed with chromium or nickel are resistant to corrosion
? Aluminium is mixed with copper, manganese and silicon for aircraft body production as the alloy
is stronger but still has a low density
? Reactivity series
? The chemistry of the metals is studied by analyzing their reaction with water dilute acid and
oxygen
? Based on these reaction a reactivity series of metals can be produced
? The series can be used to place a group if metals in order of reactivity based on the observation
of their reactions with water, acid and oxygen
? Reactivity series
? Potassium , sodium , lithium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead,
hydrogen, copper, silver gold and platinum
? Reactions with aqueous ions and oxides
? The reactivity of metals increases going up the reactivity series
? This means that a more reactive metal can displace a less reactive metal from its oxide by
heating
? As magnesium is above copper in the reactivity series, magnesium is more reactive so can
displace copper
? CuO + Mg ? Cu + MgO
? Displacement reactions between metals and aqueous solutions of metal salts
? Any metal will displace another metal that is below it in the reactivity series
? This is because more reactive metals lose electrons and form ions more readily than less
reactive metals making them better reducing agents.
? The less reactive metal is a better electron acceptor than the more reactive metal thus the less
reactive metal is reduced
? Zn + CuSO4 (aq) ? ZnSO4 (aq) + Cu
? Thermal decomposition reactions
? Compounds decompose or breakdown when they are heated to sufficiently high temperatures
? CaCO3 ? CaO + CO2
? Thermal decomposition of metal hydroxides
? Most metal hydroxides undergo thermal decomposition
? Water and the corresponding metal oxide are products formed
? Zn(OH)2  ? ZnO + H2O
? Thermal decomposition of metal carbonates
? The metal oxide and carbon dioxide are the products formed
? MgCO3 ? MgO + CO2
? Group 1 carbonates do not decompose when heated due to high thermal stability
? Thermal decomposition of metal nitrates
? Group 1 nitrates decompose forming the metal nitrite and oxygen
? 2NaNO3 ? 2NaNO2 + O2
? Other metal nitrates decompose to form metal oxide, nitrogen dioxide and oxygen
? 2Cu(NO3)2 ? 2CuO + 4NO2 + O2
? Aluminium although placed high in reactivity series does not react with oxygen because the surface of
aluminium reacts with oxygen in air to form a protective coating of aluminium oxide
? It is tough, unreactive and corrosion resistant therefore prevents aluminium from reacting with water
Extraction of metals
? Extraction of ores from the Earth’s crust
? The earth's crust contain metals and metal compounds such as gold, iron oxide and aluminium
oxide
? When found these are often mixed with other substances, to be useful they have to be extracted
from their ores
? Reactivity series and extraction
? The position of the metal determines the method of extraction
? The metals which place higher up in the series, above carbon have to be extracted using
electrolysis
? Metals lower down the series can be extracted by heating with carbon
? Extraction of zinc
? The ore is zinc blende (ZnS)
? This is burned in the air to form the oxide
¦ 2ZnS + 3O2 ? ZnO + 3SO2
? The oxide is heated with carbon in a furnace, where it is reduced to zinc
¦ ZnO + C ? Zn + CO
¦ 2ZnO + C ? 2Zn + CO2
? Zinc distills out of the furnace
? Extraction of iron
? The ore is called haematite
? Haematite, coke (carbon) and limestone are added to a furnace
? Carbon dioxide is formed (reaction between coke and oxygen and decomposition of limestone)
¦ C + O2 ? CO2
¦ CaCO3 ? CaO + CO2
? Carbon dioxide gets reduced to carbon monoxide
¦ CO2 + C ? 2CO
? Carbon monoxide reduces the iron oxide(haematite) to iron
¦ Fe2O3 + 3CO ? 2Fe + 3CO2
? The impurity in the ore is sand (silicon 4 oxide). This reacts with calcium oxide to form slag
¦ CaO + SiO2 ? CaSiO3 (slag)
? Molten slag floats on molten iron which can be run off separately and used as building material
? Extraction of aluminium
? Main ore of aluminium is called bauxite
? It is changed to pure aluminium oxide (alumina)
? Electrodes are made of carbon so oxygen reacts with carbon and does not form on the anodes
? Electrolyte is molten mixture of pure aluminium oxide dissolved in cryolite
¦ The point in cryolite is to lower the temperature from approximately 2000 to 900 degrees
and make the extraction more economically viable
? Reaction at cathode
¦ Al3+ + 3e- ? Al
? Reaction at anode
¦ 2O2- ? O2 + 4e-
Page 5


Behaviour of metals
? Physical properties of metals
? Shiny
? Good conductors of heat and electricity
? High density
? Malleable and ductile
? Usually solid at room temperature
? Sonorous (makes bell-like sounds when struck)
Chemical properties of metals
? The chemistry of metals is studied by analysis their reactions with water, dilute acid and oxygen
? Based on those reactions, a reactivity series of metals can be produced
? Reactivity with water
? Some metals react with water, either warm or cold or with steam
? Metals that react with cold water form a metal hydroxide and hydrogen gas
? For example, Ca + 2H2O ? Ca(OH)2 + H2
? Metals reacting with steam form metal oxide and hydrogen gas
? For example, Zn + H2O ? ZnO + H2
? Reactivity with acids
? Most metals react with dilute acids such as HCl
? When acids and metals react, the hydrogen atom in the acid is replace by the metal atom to
produce a salt and hydrogen gas
? For example, Fe + 2HCl ? FeCl2 + H2
? Reactivity with oxygen
? Unreactive metals such as gold and copper do not react with acids
? Some reactive metals such as alkali metals react with oxygen
? Copper and iron can also react with oxygen although much more slowly
? When metals react with oxygen, a metal oxide is formed for example copper
? For example, 2Cu + O2 ? 2CuO
? Alloys
? An alloy is a mixture of 2 or more metals or a metal and a nonmetal
? Alloys often have properties that can be very difficult to the metals they contain, for example
they can have more strength, hardness or resistance to corrosion or extreme temperatures
? Alloys contain atoms of different sizes, which distorts the normally regular arrangements of
atoms in metals
? This makes it more difficult for the laters to slide over each other, so alloys are usually much
harder than the pure metal
? Common alloys
? Brass is an alloy of copper and zinc and is much stronger than either metal
? Alloys of iron with tungsten are extremely hard and resistant to high temperatures
? Alloys of iron mixed with chromium or nickel are resistant to corrosion
? Aluminium is mixed with copper, manganese and silicon for aircraft body production as the alloy
is stronger but still has a low density
? Reactivity series
? The chemistry of the metals is studied by analyzing their reaction with water dilute acid and
oxygen
? Based on these reaction a reactivity series of metals can be produced
? The series can be used to place a group if metals in order of reactivity based on the observation
of their reactions with water, acid and oxygen
? Reactivity series
? Potassium , sodium , lithium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead,
hydrogen, copper, silver gold and platinum
? Reactions with aqueous ions and oxides
? The reactivity of metals increases going up the reactivity series
? This means that a more reactive metal can displace a less reactive metal from its oxide by
heating
? As magnesium is above copper in the reactivity series, magnesium is more reactive so can
displace copper
? CuO + Mg ? Cu + MgO
? Displacement reactions between metals and aqueous solutions of metal salts
? Any metal will displace another metal that is below it in the reactivity series
? This is because more reactive metals lose electrons and form ions more readily than less
reactive metals making them better reducing agents.
? The less reactive metal is a better electron acceptor than the more reactive metal thus the less
reactive metal is reduced
? Zn + CuSO4 (aq) ? ZnSO4 (aq) + Cu
? Thermal decomposition reactions
? Compounds decompose or breakdown when they are heated to sufficiently high temperatures
? CaCO3 ? CaO + CO2
? Thermal decomposition of metal hydroxides
? Most metal hydroxides undergo thermal decomposition
? Water and the corresponding metal oxide are products formed
? Zn(OH)2  ? ZnO + H2O
? Thermal decomposition of metal carbonates
? The metal oxide and carbon dioxide are the products formed
? MgCO3 ? MgO + CO2
? Group 1 carbonates do not decompose when heated due to high thermal stability
? Thermal decomposition of metal nitrates
? Group 1 nitrates decompose forming the metal nitrite and oxygen
? 2NaNO3 ? 2NaNO2 + O2
? Other metal nitrates decompose to form metal oxide, nitrogen dioxide and oxygen
? 2Cu(NO3)2 ? 2CuO + 4NO2 + O2
? Aluminium although placed high in reactivity series does not react with oxygen because the surface of
aluminium reacts with oxygen in air to form a protective coating of aluminium oxide
? It is tough, unreactive and corrosion resistant therefore prevents aluminium from reacting with water
Extraction of metals
? Extraction of ores from the Earth’s crust
? The earth's crust contain metals and metal compounds such as gold, iron oxide and aluminium
oxide
? When found these are often mixed with other substances, to be useful they have to be extracted
from their ores
? Reactivity series and extraction
? The position of the metal determines the method of extraction
? The metals which place higher up in the series, above carbon have to be extracted using
electrolysis
? Metals lower down the series can be extracted by heating with carbon
? Extraction of zinc
? The ore is zinc blende (ZnS)
? This is burned in the air to form the oxide
¦ 2ZnS + 3O2 ? ZnO + 3SO2
? The oxide is heated with carbon in a furnace, where it is reduced to zinc
¦ ZnO + C ? Zn + CO
¦ 2ZnO + C ? 2Zn + CO2
? Zinc distills out of the furnace
? Extraction of iron
? The ore is called haematite
? Haematite, coke (carbon) and limestone are added to a furnace
? Carbon dioxide is formed (reaction between coke and oxygen and decomposition of limestone)
¦ C + O2 ? CO2
¦ CaCO3 ? CaO + CO2
? Carbon dioxide gets reduced to carbon monoxide
¦ CO2 + C ? 2CO
? Carbon monoxide reduces the iron oxide(haematite) to iron
¦ Fe2O3 + 3CO ? 2Fe + 3CO2
? The impurity in the ore is sand (silicon 4 oxide). This reacts with calcium oxide to form slag
¦ CaO + SiO2 ? CaSiO3 (slag)
? Molten slag floats on molten iron which can be run off separately and used as building material
? Extraction of aluminium
? Main ore of aluminium is called bauxite
? It is changed to pure aluminium oxide (alumina)
? Electrodes are made of carbon so oxygen reacts with carbon and does not form on the anodes
? Electrolyte is molten mixture of pure aluminium oxide dissolved in cryolite
¦ The point in cryolite is to lower the temperature from approximately 2000 to 900 degrees
and make the extraction more economically viable
? Reaction at cathode
¦ Al3+ + 3e- ? Al
? Reaction at anode
¦ 2O2- ? O2 + 4e-
? The carbon anodes burn away in oxygen and is replaced periodically
? Uses of aluminium
? Aeroplane bodies
? Overhead power cables
? Sauce pans
? Food cans
? Window frames
? Uses of copper
? Electrical wires
? Water pipes
? Uses of steel
? Mild steel
¦ 0.25% carbon
¦ Car body panels, wires
¦ Soft and malleable
? High carbon steel
¦ 0.5 - 1.4% carbon
¦ Tools and chisels
¦ Hard
? Low alloy steels
¦ 1-5% of other metals
¦ Construction, bridges, high speed tools
¦ Hard and strong, low ductility and malleability
? Stainless steel
¦ 20% chromium and 10% nickel
¦ Cutlery and sinks, chemical plants
¦ Strong and resistant to corrosion