Chemistry - Metals and Non-Metals Class Notes PDF

Chemistry Metals and Non-metals in One Shot SUNIL BHAIYA Today’s Targets 1 Introduction to Types of Elements 2 Physical Properties of Metals and Non-metals 3 How Reactivity Series Was Built?! 4 Ionic Compounds and Its Properties 5...

Chemistry Metals and Non-metals in One Shot SUNIL BHAIYA Today’s Targets 1 Introduction to Types of Elements 2 Physical Properties of Metals and Non-metals 3 How Reactivity Series Was Built?! 4 Ionic Compounds and Its Properties 5 Metallurgy 6 Corrosion, Its Types and Ways to Prevent It  Extra! Extra! Extra! (i) NCERT Activities Covered with Explanation (ii) Experiments (iii) NCERT Chipa Hua Gyaan Covered Introduction to Types of Elements  Types of Elements Metals Non-metals Metalloids Noble Gases Some common metals are: Lithium (Li), Sodium (Na), Potassium (K), Magnesium (Mg), Calcium (Ca), Aluminium (Al), Copper (Cu), Zinc (Zn), Silver (Ag), Gold (Au) etc.  Types of Elements Metals Non-metals Metalloids Noble Gases Non-metals are: Carbon (C), Phosphorus (P), Sulphur (S), Selenium (Se), Iodine (I), Hydrogen (H), Nitrogen (N), Oxygen (O), Fluorine (F), Chlorine (Cl), Bromine (Br)  Types of Elements Metals Non-metals Metalloids Noble Gases Common recognised metalloids are: Boron (B), Silicon (Si), Germanium (Ge), Antimony (Sb), Arsenic (As), Tellurium (Te)  Types of Elements Metals Non-metals Metalloids Noble Gases Noble gases are: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn) Kya Bolti Public? Physical Properties of Metals and Non-metals  Yes or No Are mercury and bromine found in liquid state at room temperature (25 °C)? A. Yes B. No  Physical Properties of Metals and Non-metals The resistance offered by a substance against cutting or scratching. The ability of metals to reflect light due to which they have a shiny surface.  Physical Properties of Metals and Non-metals The ability of metals to be converted into thin sheets on application of compressive forces. The ability of metals to be converted into thin wires on application of tensile forces. Physical Properties of Metals and Non-metals NCERT ACTIVITY DISCUSSION  Q. DISCUSSION AND CONCLUSION (i) What do you observe after sometime and does metal wire melt? (i) We observe that on heating the wire near the clamp, after some time the pin falls down. This shows that the heat flows through the wire and melts the wax. Further, the wire does not melt even after heating for a long time. This shows that metals have high melting points. NCERT ACTIVITY DISCUSSION  Q. DISCUSSION AND CONCLUSION (i) Will the bulb? What does this indicate? (i) The bulb glows. This shows that electric current flows through the metal. (ii) Why are electric wires coated with PVC? (i) PVC or any other rubber like material is used because they are poor conductors of electricity.  FUN FACT Gold is the most malleable metal. Platinum is the most ductile metal. (Gold according to NCERT) Diamond is the best conductor of heat. Silver is the best conductor of heat in case of metals followed by copper. Order of electricity conduction in case of metals will be: Silver > Copper > Gold > Aluminium Kya Bolti Public?  Reaction with oxygen Reaction with water How Reactivity Series Reaction with dilute acids Was Built?! Reaction with salt solutions of other metals  Give a Thought The metal which reacts at a lower temperature than the one which doesn’t react is more reactive. Is this true or false? A. True B. False Metal ‘A’ reacts at a lower temperature than another metal ‘B’. It means (A) is more reactive than ‘B’.  Give a Thought The metal which reacts more vigorously and generates large amount of heat and light energy than another metal when reacting with a same substance is more reactive. A. True B. False ‘Metal A’ reacts at a faster speed than another metal ‘B’ and releases more amount of heat and light energy as compared to metal ‘B’ when both reacts with a same substance at a same condition.  Reaction of Metals with Oxygen Metal Oxygen Metal oxide Room temp. Strong Heating  Metal Product Colour of Colour of flame Room temp. or formed product on low heating Potassium Sodium Calcium Magnesium Aluminium Zinc Iron Lead Copper Silver, Gold And Platinum  Metal Product Colour of Colour of flame Strongly heating formed product in presence of Potassium oxygen Sodium Calcium Magnesium Aluminium Zinc Iron Lead Copper Silver, Gold And Platinum  Conclusion (i) Potassium and sodium are most reactive but which is more reactive between both of them. (ii) Silver, Gold and Platinum are least reactive but which is more reactive amongst all of them.  Conclusion (iii) Calcium, Aluminium and Magnesium are reactive metals but which is more reactive amongst all of them. (iv) Zinc and Iron are more reactive than Lead and Copper but less reactive than K, Na, Ca, Mg and Al but which is more reactive between Lead and Copper. Jaldi Se Batao Beta Ji All metal oxides/hydroxides only basic in nature?  Reaction of Metals with Water Metal Water Metal oxide Hydrogen Dissolves in Water Metal hydroxide Reaction of Metals with Cold Water (i) Evolved hydrogen gas doesn’t catch fire. (ii) The tiny bubbles of hydrogen gas formed stick to the surface of the calcium, and hence it starts floating on the water. SODIUM AND POTASSIUM TO WATER Reaction of Metals with Hot Water (i) Evolved hydrogen gas doesn’t catch fire. (ii) The tiny bubbles of hydrogen gas formed stick to the surface of the magnesium, and hence it starts floating on the water. Reaction of Metals with Steam Conclusion: We can only arrange those metals that react with cold or hot water in decreasing order of their reactivity which is: K > Na > Ca > Mg  Give a Thought Why sodium and potassium are stored in kerosene/mineral oil?  Give a Thought Why sodium and potassium are stored in kerosene/mineral oil? Sodium and potassium are highly reactive metals and react with air (oxygen/moisture) and catches fire. To prevent the supply of air they are kept in kerosene/mineral oil.  Ek Aur Ek Aur! Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.  Ek Aur Ek Aur! Aluminium is a highly reactive metal, yet it is used to make utensils for cooking. Aluminium (Al) is a good conductor of heat, has high melting point and forms a protective and unreactive layer of aluminium on itself.  Reaction of Metals with Dilute Acids The more reactive metals do not react with the same vigour with acids and it can be understood in terms of the rate of the effervescence of hydrogen gas.  Reaction of Metals with Dilute Acids The more reactive metals do not react with the same vigour with acids and it can be understood in terms of the rate of the effervescence of hydrogen gas.  Reaction of Metals with Dilute Acids We can also identify the most reactive metal by placing a thermometer. The one in which maximum rise in temperature is seen is giving the reaction at a faster rate in the same amount of time.  Reaction of Metals with Dilute Acids What happens if the reaction takes place in presence of dilute nitric acid? Metal (Mg and Mn) + dilute nitric acid -> Salt + Hydrogen gas Other Metals + dilute nitric acid ->  Aqua Regia Aqua regia, which in Latin means ‘royal water’ is a mixture of concentrated nitric acid and hydrochloric acid in the ratio of 1:3 by volume. It is a highly corrosive and fuming liquid. It is one of the few reagents that can dissolve gold and platinum. Reaction of Metals with Solutions of Other Metals Reaction of Metals with Solutions of Other Metals Reactivity/Activity Series of Metals  Reaction of Non-metals with Oxygen and Water Non-metal Oxygen Non-metal oxide Generally, non-metals don’t react with water because they can’t displace hydrogen (non-metal) from water.  Reaction of Non-metals with Oxygen and Water Non-metal Oxide Water Acid Non-metallic oxides are acidic in nature: CO2, SO2, SO3 etc. Non-metallic oxides can be neutral in nature as well: CO, H2O, N2O etc. Kya Bolti Public? Ionic Compounds and Its Properties  Sodium chloride (NaCl) Element Electronic Configuration Na Cl  Magnesium chloride (MgCl2) Element Electronic Configuration Mg Cl Metallurgy Give a Thought The metals obtained from seawater are in: A. Elemental form B. Compound form  Conclusion The major source of metals (whether in the free state or the combined state) is the Earth’s crust. Some metals (Na, K etc.) which form soluble salts are also found to occur in the seawater in the form of their soluble salts. Give a Thought Metals like gold and platinum are found in: A. Elemental form B. Compound form Conclusion  Minerals and Ores Metals occur naturally in the form of elements or compounds in the earth’s crust or seawater and are called minerals. The earthly and rocky impurities that are associated with the mineral are called gangue or matrix.  Minerals and Ores Let us consider two minerals: - Clay (contains Aluminium) - Bauxite (contains Aluminium)  Minerals and Ores Let us consider two minerals: - Clay (contains Aluminium) - Bauxite (contains Aluminium) – Extraction is done from this only!  Minerals and Ores Metals are extracted from some minerals only because: - process of extraction of metal from that mineral is not economical - there are certain impurities that are difficult to remove.  Conclusion The minerals from which metals can be extracted economically and conveniently are called ores. Thus, all ores are minerals but all minerals are not ores. Note: It is interesting to note that the ores of most of the metals exist as oxides. This is because oxygen is a very reactive element and is abundantly found on the earth. Ores of Some Common Metals STEP I: Crushing and Grinding of Ore  STEP II: Concentration/Dressing/Benefaction/ Enrichment of Ore Importance Before extracting the metal, it is important to remove gangue or matrix! Principle of separation of gangue from ore: The differences between the physical or chemical properties of the gangue and the ore. BACCHA LOGG BE LIKE GANGUE BE LIKE  STEP III: Extraction of Metal from Concentrated Ore (i) Extraction of low reactivity metals (At low in the reactivity series of metals) (ii) Extraction of medium reactivity metals ( At middle in the reactivity series of metals) (iii) Extraction of high reactivity metals (At top in the reactivity series of metals) Note: Least reactivity metals like Gold and Platinum are found in the free/native state.  Step III: Extraction of Metal from Concentrated Ore (Metals of low reactivity) Cu, Hg and Ag are metals of low reactivity. Let’s discuss how Copper and Mercury are extracted from their most common ores, i.e. sulphide ores. Copper Mercury Ore  Give a Thought It is easy to extract metal from its oxide or its carbonate and sulphide? It is easy to extract a metal from its oxide rather than sulphide or carbonate. So, carbonate or sulphide ores are first converted into oxides.  Step III: Extraction of Metal from Concentrated Ore (Metals of low reactivity) Roasting: Strongly heating the sulphide ore in excess of air below melting point of metal. In case of metals of low reactivity the metal oxide automatically reduces to metal on action of heat. Step III: Extraction of Metal from Concentrated Ore (Metals of low reactivity) Let’s analyse the case of copper! Step III: Extraction of Metal from Concentrated Ore (Metals of low reactivity) Let’s analyse the case of mercury!  Summary of All Steps (Metals of low reactivity) Step I Crushing and Grinding of Ore Step V Step II Refining/Purification of Metal Concentration of Ore Step IV Step III Auto-reduction Roasting (Sulphide Ore) (Conversion of metal oxide to metal)  Step III: Extraction of Metal from Concentrated Ore (Metals of medium reactivity) Zn, Fe and Pb are metals of medium reactivity which are found in the form of their oxides, sulphides or carbonates. Will the first two steps be the same in this case as well?  Step III: Extraction of Metal from Concentrated Ore (Metals of medium reactivity) Zn, Fe and Pb are metals of medium reactivity which are found in the form of their oxides, sulphides or carbonates. Ab btao sulphide or carbonate ko phle oxide bnaenge ya nhi?  Step III: Extraction of Metal from Concentrated Ore (Metals of medium reactivity) Roasting Calcination (i) Used for sulphide ore. (i) Used for carbonate ore. (ii) Sulphide ore is strongly heated (ii) Carbonate ore is strongly in excess of air below the melting heated in absence of air below point of metal. the melting point of metal. (iii) Metal sulphide + Oxygen -> (iii) Metal carbonate -> Metal Metal oxide + Sulphur dioxide gas oxide + Carbon dioxide gas (iv) Sulphur dioxide gas is (iv) Carbon dioxide gas is evolved. evolved.  Step III: Extraction of Metal from Concentrated Ore (Metals of medium reactivity) Let’s analyse the case of zinc! Ore Roasting  Step III: Extraction of Metal from Concentrated Ore (Metals of medium reactivity) Let’s analyse the case of zinc! Ore Calcination  Step III: Extraction of Metal from Concentrated Ore (Metals of medium reactivity) After roasting or calcination we get metal oxide. Now, what next?! Reduction of metal oxide to metal Reducing agents like carbon, aluminium etc. are used. Step III: Extraction of Metal from Concentrated Ore (Metals of medium reactivity) Reduction of metal oxide by carbon (coke) - Smelting  Step III: Extraction of Metal from Concentrated Ore (Metals of medium reactivity) Reduction of metal oxide by aluminium - Aluminothermy  Give a Thought Why carbon is not used in case Mn? Aluminium is more reactive than Mn. It means it can easily displace them and forms aluminium oxide. Doing the same cannot be satisfactorily done with carbon.  Application of Aluminothermy Reduction of metal oxide by aluminium - Aluminothermy The reaction is therefore used for welding the broken parts of iron machinery, railway tracks etc. The reaction is known as thermite reaction. Thermite reaction is a type of displacement, exothermic and redox reaction.  Summary of All Steps (Metals of medium reactivity) Step IV Step I Reduction to metal Crushing and oxide to metal Step III Grinding of Ore (Using reducing Roasting (Sulphide Ore) agent) Step II Concentration of (Oxide Ore) Metal oxide Ore Step III Calcination (Carbonate Ore) Step V Refining/Purification of metal  Step III: Extraction of Metal from Concentrated Ore (Metals of high reactivity) K, Na, Ca, Mg and Al are metals of high reactivity. Let’s discuss how they are extracted from halides or oxides. Sodium Aluminium Ore  Step III: Extraction of Metal from Concentrated Ore (Metals of high reactivity) After concentration of ore, can we use reduction of metal oxide through reducing agents like carbon? No The oxides/chlorides of highly reactive metals are quite stable, cannot be reduced by any reducing agent. They have more affinity for oxygen/chlorine.  Step III: Extraction of Metal from Concentrated Ore (Metals of high reactivity) A special reduction process, i.e. electrolytic reduction is used for highly reactive metals like K, Na, Ca, Mg and Al. Electrolytic Reduction The electrolytic reduction is a type of electrolysis. The oxides and chlorides of metals in fused/molten state are electrically reduced by using this method. Electrolytic Reduction Summary of All Steps (Metals of high reactivity) Step I Crushing and Grinding of Ore Step II Concentration of Ore Step III Electrolytic Reduction Refining/Purification of Metals Metals obtained after extraction still contains some impurities which are removed by: (i) Electrolytic refining (ii) Distillation (iii) Liquefaction (iv) Vapour phase refining (v) Zone refining  Electrolytic Refining (i) The set-up consists of an electrolytic tank that contains copper sulphate solution.  Electrolytic Refining (ii) A thick block of impure copper metal is connected to the positive terminal, i.e. anode.  Electrolytic Refining (ii) A thin strip of pure copper metal is connected to the negative terminal, i.e. cathode. Electrolytic Refining  Give a Thought What happens to the impurities then? Soluble Impurities Insoluble Impurities Kya Bolti Public? Corrosion, Its Types and Ways to Prevent It  Corrosion It is a surface deterioration process of metals in which they convert to a more stable form, i.e. oxides, sulphides, carbonates and more, due to the attack of atmospheric gases. Corrosion and Its Types  Give a Thought Can rusting happen without having any one factor, i.e. oxygen or water-vapour? A. Yes B. No For rusting of iron to happen both factors, i.e. oxygen and water- vapour are required. Let’s Analyse! Will rusting happens in this case? Yes, rusting will happen.  Let’s Analyse! Will rusting happens in this case? (i) Air from above: (i) Air from above: (ii) Normal water: (ii) Boiled water: Let’s Analyse! Will rusting happens in this case? No, rusting won’t happen. Corrosion and Its Types Corrosion and Its Types  Pros of Corrosion Pros of Corrosion – Patina Patina seems to be helpful for some of the metals like Copper (Cu), which on oxidation forms an impervious protective layer that protects further corrosion (here tarnishing) of metal.  Cons of Corrosion Cons of Corrosion – Rusting Rust is a flaky (non-sticky) layer that is very brittle and peels-off. It then exposes the fresh iron layer to moisture and oxygen. This continuous cycle makes iron objects weak and can collapse buildings and bridges, break oil pipelines and more.  Ways to Prevent Corrosion - Rusting The below methods are used to prevent the rusting of iron: (a) Barrier Protection (b) Sacrificial Protection (c) Alloying  Ways to Prevent Corrosion - Rusting (a) Barrier Protection: In this a layer is introduced between iron and factors that cause rusting, i.e. oxygen and water vapour. Some of the ways are: (i) Painting (ii) Applying oil or grease  Give a Thought Are painting and greesing permanent solutions to prevent rusting? A. Yes B. No  Ways to Prevent Corrosion - Rusting (b) Sacrificial Protection: In this a layer of more reactive metal is placed on a less reactive. The more reactive prevents oxygen and water to come in contact with iron and gets corroded in place of iron. One such way is galvanisation.  Ways to Prevent Corrosion - Rusting The galvanized iron sheets are used to make: (i) Buckets (ii) Drums (iii) Sheds  Give a Thought Is galavanisation a permanent solution to prevent rusting? A. Yes B. No  Give a Thought If the layer of Zinc breaks on iron. Will iron rust or zinc?  Ways to Prevent Corrosion - Rusting (c) Alloying: In alloying, two or more than two metals or metals along with small amount of non-metals are mixed. It is a permanent solution to prevent corrosion.  Objectives of Alloying (i) To increase hardness. (ii) To increase tensile strength. (iii) To reduce melting point. (iv) To increase resistance to corrosion. (v) To decrease electrical conductivity.  Ways to Prevent Corrosion - Rusting Pure iron is soft, stretches easily when hot and prone to rust. Iron is alloyed with carbon and it becomes hard and strong. More to Know: Stainless Steel: Iron + Chromium + Nickel -Provides hardness. -Not prone to rusting. -Resistance to corrosion. -Used to create utensils. -Prevents from getting stains.  Ways to Prevent Corrosion - Rusting Pure gold is 24 carat which is soft and hence, it is not used to make jewellery. In India, 22 carat gold is ornamental gold. This means 22 parts by weight of gold is alloyed with 2 parts by weight of either copper or silver.  Common Alloys Alloy Composition Properties Important Uses (i) Brass Copper (80%) and Malleable, strong, Utensils, screws Zinc (20%) resists corrosion etc. (ii) Bronze Copper (90%) and Strong and resists Coins, bells etc. Tin (10%) corrosion (iii) German Copper (60%), Zinc Shines like silver, Electroplating silver (20%) and Nickel resistant to (20%) corrosion (iv) Solder Lead (50%) and Tin Lower melting For joining (50%) point than lead electrical wires and tin together.  Common Alloys Note: The alloys of mercury with any other metal is called amalgam.  Ways to Prevent Corrosion - Anodising Anodising is an electrolytic passivation process that is used to increase the natural oxide layer on surface of metal parts. It is generally done for aluminium and its alloys. How Anodising is Done for Aluminium? Kya Bolti Public?