Metals and non metals.pdf

Metals and Non- metals What are Metals ? Out of 118 elements known: 93 are METALS 18 are NON-METALS 7 are METALLOIDS  METALS The metal may be defined as an element which leads to the formation of positive ions easily Or readily by losing its electrons. For example-...

Metals and Non- metals What are Metals ? Out of 118 elements known: 93 are METALS 18 are NON-METALS 7 are METALLOIDS  METALS The metal may be defined as an element which leads to the formation of positive ions easily Or readily by losing its electrons. For example- Zinc, Iron, Copper etc. PHYSICAL PROPERTIES PHYSICAL CHANGES Metallic lustre :- The metals are consists of shiny 🌟surface in their pure state and this property is known as metallic lustre. For example - Gold, silver, platinum etc.  Hardness- the hardness of metals varies from one to the other. Mostly we see the hard nature of metals but in case of alkali metals like sodium ( can be easily cut with 🔪knife), potassium and lithium are of soft nature. Malleability- the metals contains this property in which they can be easily beaten into thin sheets. For example- Gold, silver are most malleable metals.  Ductility- the property of metals by which they can be easily drawn into thin wires is known as ductility. For example- Gold is the most ductile metal. Electrical conductivity- the metals, in their solid States are found to be good conductor of ⚡electricity. The conduction of electric current is due to the flow of electrons present in them while it depends on the metal taken,whether it is good conductor Or not because all the metals do not show same conductivity.  Sonority - metals are sonorous in nature as when they strikes to a hard surface produces sound 🔊. For example - school 🔔🔔🔔bells. Good conductor of heat - Except lead and mercury which are poor conductor of heat all other metals are good conductor of heat. For example - silver and copper are best conductor of heat.  Melting and boiling point :- The metals are generally consists of higher melting and boiling point. Highest melting point- tungsten Low melting point - gallium and caesium ( if kept on palm 🤲Gallium and Caesium easily melts.) Why do we need to know chemical properties of Metals and Non-metals? Why do we need to know chemical properties of Metals and Non-metals? CHEMICAL PROPERTIES OF METALS ¤ The REACTIVITY SERIES is the arrangement of metals in a series on the basis of their reactive nature and also their tendency to loose the electrons for cation formation. ¤ According to the decreasing activity, metals are arranged in a reactivity series which is shown ahead.  Reaction of Metal with oxygen Metal + Oxygen → Metal oxide ( burning in air or oxide formation)  Mostly metal oxides are basic in Nature. They react with acids to form salt and water. But some of them show both acidic and basic properties. Such metal oxides that react with both acids/base to form salt and water are known as AMPHOTERIC OXIDES! Metal oxides are mostly insoluble in water but some of them dissolve to form alkali!  Reactivity of Metals with Oxygen! Sodium and Potassium react vigorously that they catch fire in open. They are stored dipped in Kerosene oil. At room temperature, magnesium and aluminium are covered with their respective oxides,. This prevents their further oxidation. Iron doesn’t burn but its filings does. Copper doesn’t burn but it is covered in its oxide (CuO) which gives it a black appearance. Silver and Gold do not react with oxygen even at high temperature. Anodising - thick oxide layer of aluminium is formed. Clean Al article is made anode and electrolysed with dilute HCl as to evolve oxygen at anode which reacts with Al to form a thick oxide layer for protection and further the layer is painted to give good finishing. Reaction of Metal with water Metal + water→ Metal oxide + hydrogen gas Metal oxide + water → Metal hydroxide  Potassium and Sodium : 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g) + heat 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g) + heat Calcium : Bubbles of hydrogen gas stick to calcium during the reaction and makes it float! Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g) Aluminium and Iron : 2Al(s) + 3H2O(g) → Al2O3(s) + 3H2(g) 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g) Reaction of Metal with acids Metal + dilute acid → Salt + hydrogen Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)  Metal + dilute HNO3 → Salt + NO2/ NO/N2O + H2O HNO3 is a strong oxidising agent. When most metals react with it, hydrogen gas is not produced. Why? Because it oxides the hydrogen gas produced to water, and gets reduced itself to nitrogen oxide (N2O, NO, NO2). Aqua regia - ( Royal water in Latin) fresh mixture of conc. HCl and conc. HNO3 in 3:1 ratio. This is able to dissolve gold but alone any of this acid can't do so. Mixture is fuming liquid and highly corrosive. Have the ability to dissolve platinum and gold.  Reaction of Metal with solution of other metal salts Displacement reaction Metal A+ Salt solution of B → Salt solution of A + Metal B Cu(s) + 2AgNO3(aq) →Cu(NO3)2(aq) + 2Ag(s)  NON-METALS The non+metal may be defined as an element which leads to the formation of negative ions or anions by gaining electrons. For example- Chlorine, hydrogen, iodine, sulphur etc. PHYSICAL PROPERTIE OF PHYSICAL CHANGES NON-METALS Lustre :- The non-metals do not consists of shiny 🌟surface and thus shows now lustrous property. For example - Exception allotropes of carbon ( diamond and graphite) , iodine have lustre.  Hardness- most of the non-metal shows soft nature. Exception- Diamond💎the allotrope of carbon is the hardest non-metal. Malleability- the non-metals do not contains this property in which they can be easily beaten into thin sheets.  Ductility- Non-metals cannot be easily drawn into thin wires. Hence are non ductile in nature. Electrical conductivity and heat energy - the non- metals are bad conductor of ⚡electricity as well as heat. Graphite allotrope of carbon is a good conductor of heat and electricity.  Melting and Boiling point- Non-metals have lower melting as well as boiling point. But in case like B, Si, C are solid in nature and this have higher melting point then others comparatively. Brittleness - non-metal shows brittle nature. Sulphur shows brittle behavior when hammered breaks into pieces. CHEMICAL PROPERTIES OF NON-METALS  Non-metals basically are electron acceptor which leads to anion formation and hence Non-metals do not reacts with water and dilute acids to form hydrogen gas.  Reaction of Non-metal with Conc. Acid upon heating Non-Metal + conc. Acid → Salt /oxides S(s) + 2H2SO4(conc.) → 3SO2(g) + 2H2O(l) Reaction of Metal with non-metal  IONIC BOND FORMATION We know metals have the tendency to lose the electrons to make positive ion or cation, Similarly non- metals have the property to gain electrons to form a negative ion or anion. Ionic bond is the type of chemical bond formation taking place between the metal and non metal by complete transfer of electrons from one atom to the other.  Examples given ahead are showing the formation of ionic bond by complete transfer of electrons between the atoms of metal and non metal. Here Na, Mg are metals and Cl is non- metal.  PROPERTIES OF IONIC COMPOUNDS  Physical nature ❖ Solids ❖ Hard due to strong force of attraction between cation and anion. ❖ Are brittle in nature, easily breaks when hammered. Melting and boiling points ❖ Have higher melting and boiling point ❖ Because of the amount of energy required to break the strong attractive force.  Solubility ❖ Are soluble in water ❖ Insoluble in solvents. E.g. Kerosene, petrol etc. Conduction of electricity ❖ Solid ionic compounds do not conduct electricity as theirs ions do not forms due to strong force of attraction. ❖ Molten state of ionic compounds leads to conduction of electricity as there is less force of attraction between the cation and anion and thus moves to separate electrode to conduct electricity. What is not true in case of sodium metal in the following (a) kept in water (b) can be easily cut with knife (c) reactive metal (d) reacts with moisture and air (e) kept in kerosene Elements that can donate electrons to form positive ions are (a) Metalloid (b) Non-metals (c) Metals (d) Alloy Electrical wires generally have the coating of insulating material and this material generally uses (a) graphite (b) diamond (c) PVC (d) sulphur (e) all of the above Dullness is a property which is not shown by ----- (a)Non-metal (b) Metal (c) metalloid (d) none of the them The ability of the metals to be drawn into thin sheets is known as (a) Malleability (b) ductility (c) both a and b (d) sonority ----- is used for making cooking utensils because of its high melting point and good thermal conductivity. (a) Na (b) Mg (c) Al (d) C ----- is the metal which do not react with cold as well as hot water. (a) K (b) Na (c) Cu(d) Ag  OCCURRENCE OF METALS ❖ Major source of occurrence is Earth's crust ❖ Sea water contains soluble salts in it. E.g. NaCl  EXTRACTION OF METALS ❖ The process through which we are able to get the pure metal from its ore is known as extraction of metals.  Enrichment of Ores ❏ When the metals are extracted from earth's crust or mined they usually contains a lot of unwanted substance or impurities with them which is known as Gangue. ❏ These impurities should be removed to get a pure metal which involves the process based on the physical and chemical properties of gangue.  Extracting Metals Low in the Activity Series ❏ When ore of mercury cinnabar is heated it leads to mercuric oxide formation which further reacts to form mercury. ❏ 2HgS(s) + 3O2 (g) → 2HgO(s) + 2SO2(g) 2HgO(s) → 2Hg(l) + O2 (g) ❏ Similarly, copper is obtained from its ore ❏ 2Cu2S + 3O2 (g) → 2Cu2O(s) + 3SO2 (g) 2Cu2O + Cu2S → 6Cu(s) + SO2 (g)  Extracting Metals in the Middle of the Activity Series ❏ Roasting - process in which concentrated ores are heated strongly in presence of excess air. 2ZnS(s) + 3O2 → 2ZnO + 2SO2 ❏ Calcination - process in which concentrated ores are heated in absence of excess air. ZnCO3(s) → ZnO(s) +CO2(g) ❏ Reaction of metal oxide with carbon to form metal. E.g. ZnO(s) + C(s) → Zn(s) + CO(g) ❏ Thermite reaction or aluminothermy process- ( reduction with Aluminum) 3MnO2(g) + 4Al(s) → 3Mn(s) + 2Al2O3(s) Fe2O3(g) + 2Al(s) → 2Fe(l) + Al2O3(s) +heat  Extracting Metals towards top of the Activity Series Electrolytic reduction of molten sodium chloride Metal will be produced at cathode (-ve charged Non-metals will be produced at anode (+ve charged) NaCl(l) → Na+ + Cl- Sodium sodium chloride Chloride cation anion Electrolytic refining or Refining of impure metals CORROSION ❏ Corrosion may be defined as the oxidation reaction taking place on the surface of a metal in presence of water and atmospheric oxygen. Fe (s) + xH2O(l) + 3O2(g) ----> Fe2O3. xH2O(s) (Brown rust) Rusting of iron requires both presence of oxygen and water  CORROSION The slow destruction or eating up of metals by the reaction of water, some atmospheric gases like oxygen, carbon dioxide, hydrogen sulphide with metals is called corrosion. 4 Fe (s) + 3 O2 (g) + 2x H2O 2 Fe2O3.xH2O 2 Cu (s) + CO2 (g) + O2 (g) + H2O (l) CuCO3.Cu(OH)2 2 Ag (s) + H2S (g) Ag2S(s). + H2 (g) Rusting of Iron  Corrosion occurs with the following Iron and steel Aluminum undergoes oxidation but doesn't oxidize and corrode as quickly. Sodium corrodes in presence of oxygen thus needs to be stored in oil. ❏ Prevention of Corrosion ❏ Painting ❏ Oiling and greasing ❏ Galvanization - may be defined as the process of applying a zinc coating on iron. ❏ Alloy - homogenous mixture of two or more metals. (Prepared by melting the metals and then mixing them properly) ❏ Properties of alloy - :- Stronger than metals from which they are made :-Have lower melting point and lower electrical conductivity :-Are more resistant to corrosion and are harder ❏ Some common amalgam are :- ❏ Amalgum- alloy of mercury ❏ Brass - alloy of copper(80%) and zinc (20%) ❏ Bronze - alloy of copper(90%) and tin(10%)  Comparison of metals and non-metals on the basis of their chemical properties  Metals Non-metals Strong tendency to loose Have strong tendency to electrons. gain the electrons. Easily displaces the From dilute acids it hydrogen gas from dilute doesn't displaces acids hydrogen gas. Reacts with oxygen to Reacts with oxygen to produce basic oxides form acidic oxides. Reacts with hydrogen to Reacts with hydrogen to produce covalent produce Hydrides. compounds  Comparison between metals and non-metals on the basis of their physical properties Property Metals Non-metals In all 3 states Solid except Hg, Ga State of matter except Br and Cs High density Low Density except Na,Ca, k High except Melting point Low Hg,Ga,Pb, Sn Beaten into thin Malleability Brittle in nature sheets Usually no hard Hard except Na,Ca, Hardness except diamond💎 K, Pb, Hg Drawn into wires Non ductile Ductility except Na k, Ca Conduction of heat Poor or not Good conductor and electricity⚡ conductor