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Metals have very high densities - A large number of metal atoms are closely packed in the giant metallic lattice
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Metals are good conductors of heat and electricity - presence of sea of delocalised electrons(help to conduct heat and electricity)
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Metals are soft - When a force is applied, layer of metal atoms will slide over one another
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Metals are malleable and ductile - When a force is applied, layer of metals slides over one another without disrupting metallic bonds
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Metals have a high melting point - Large amount of energy is required to overcome the strong metallic bonds between lattice of positive cations and sea of delocalised electrons
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What is an alloy - mixture of a metal with one or more other elements
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Effect of alloying - makes the original metal stronger, harder and more resistive to corrosion
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How does alloying strengthen metals - Neat, regular rows of metal atoms are disrupted by the presence of a new atom of a different size. Layers of metal atoms can no longer slide over one another when a force is applied. Hence the metal is stronger and harder
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Common alloys - Steel/ Brass
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K
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Na
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Ca
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Mg
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Al
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C
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Zn
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Fe
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Sn
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Pb
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H
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Cu
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Ag
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Au
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Metal + Water = Metal hydroxide + Hydrogen
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Metal + Steam = Metal oxide +Hydrogen
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Metal + HCL = Metal Chloride + Hydrogen gas
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Metals that react with cold water - Potassium to Magnesium (decreasing vigour)
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Metals that react with steam: Potassium to Iron
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Metals that react with hydrochloric acid: Potassium to Iron
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Why does lead not react with water/steam/HCl = Formation of lead hydroxide, lead oxide, lead chloride which are all insoluble (form layer)
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Displacement - A more reactive metal displaces a less reactive metal from its salt solution/ oxide (more reactive metal in solid state/less reactive metal in ion state)
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Thermal Stability of carbonates - Thermal stability of carbonates decreases down the reactivity series
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Most thermally stable carbonates - Group 1 carbonates
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Thermal decomposition of carbonates= metal oxide + carbon dioxide
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Thermal decomposition of silver carbonate= silver + carbon dioxide + oxygen
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Electrolysis of molten ore - Potassium to Aluminium
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Reduction of carbon : Below Carbon in reactivity series
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Reduction of hydrogen : Iron - Copper
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Found chemically uncombined: Silver and Gold
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Extraction of iron - Use carbon to reduce haematite to form molten iron ( blast furnace)
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Rusting - oxidation of iron to form hydrated iron(III) oxide
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Conditions for rusting - Both oxygen and water
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Prevention of rusting: Protective layer(oil/paint), Sacrificial Metals, Use of alloys
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Protective layer (must cover entire surface): prevents iron from coming in contact with oxygen and water—prevents rusting
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Sacrificial Protection(no need to cover entire surface): Metal A is more reactive than Metal B. Metal A acts as a sacrificial metal and corrodes in the place of iron
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Example of sacrificial protection- Galvanising(Zinc)
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Use of alloys - alloys are more resistive to corrosion
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Why must we recycle metals - Metals are finite resources. It is our responsibility to conserve metals for future purposes
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Problems with mining: contribute to environmental pollution, burning of fossil fuel, contributes to unnecessary waste(take up landfill space)
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Cons of recycling: Expensive process
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Reacts with oxygen in surrounding air to form aluminium oxide. Aluminium oxide forms an impervious layer on the surface of the metal
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Prevents metal form coming into contact with the other reactant
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Prevents metal form coming into contact with the other reactant
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Hence aluminium is unreactive
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