Metals and Non Metals-10

8/3/2019 Metals and Non Metals-10

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NAME-JAYESHBIDANI(14) &

10-E


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A metal is a chemical element that is agood conductor ofboth electricity and heat and

forms cations and ionicbonds with non-metals


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Hg

Copper used asconducting wire

ELECTRONIC CONFIGURATION: Metalsgenerally have 1,2,3, valence electrons exceptHydrogen, Helium or Boron which have 1,2,3valence electrons respectively. E.g. Na ---- Na+ e

ELECTRON POSITIVE CHARACTER:Metals are electropositive in nature since theyhave a tendency to loose their valenceelectrons and acquire noble gas configuration.

DUCTILITY: Metals are ductile in nature i.e.they can be drawn into wires.

THERMALAND ELECTRICAL


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MALLAEBALITY: Metals re malleable i.e.they can be beaten into thin sheets.)

CONDUCTIVITY: Metals are very goodconductor of heat and electricity due to thepresence of valence electrons except graphite.

HARDNESS: Metals are generally hard exceptsodium and potassium which are so soft that they

can be cut with a knife easily.

Hg

Copper used asconducting wire


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Almost all metals (except gold and platinum) combine with oxygen to formmetal oxide. The reactivity of metal towards oxygen are different. Somemetals react only when heated. While there are metals which react onprolonged heating/

Sodium and Potassium react with oxygen at room temperature to form basic

oxideNa + O2------- 2Na2OMagnesium combines with oxygen not at room temperature but whenheated.

2Mg + O2 ------- 2MgoSince Magnesium reacts with O2 less readily than sodium , therefore,

magnesium is less reactive than sodium.

Copper reacts with oxygen only on prolonged heating.2Cu + O2 -------- 2CuO

Therefore, copper is less reactive than zinc. Thus the order of reactivity ofmetals with oxygen is

Na>Mg>Cu


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All metals combine with O2 to form metal oxide.

4Na + O2 ------- 2Na20These metal oxides are basic in nature i.e. they dissolves inwater to form alkali i.e. base

2Na2 + H2O --------2NaOHThe basic solution is determined by the following methods.

It turns moist red litmus paper to blue.

It turns colorless Phenolphthaleinsolution to pink.

Some metals oxides such as aluminium oxide (Al2O3), SinceOxide (ZnO) etc. show both acidic as well as Basic behaviour.

Such metal oxides are known as amphoteric oxides.Aluminium oxides react in the full manner with acids and

bases---Al2O3 + 6Hcl -------2AlCl3 + 3H2O

Al2O3 + 2NaOH ------ 2NaAlO2 + H20(sodium aluminate)


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The reactivity of metal with water is different. Some metal react with water atordinary temperature while some metals react when heated. In each case

hydrogen is evolved.Sodium and Potassium react with water at room temperatureMagnesium and zinc do not react with cold water, they react with steam.Metals like copper do not react with water even when heated at high

temperature.The order of reactivity of some metal with water is Na>Mg>Cu

Action of steam on a metal


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Metals usually displace hydrogen from dilute acids.

Only the less reactive metal like copper, silver and gold do nodisplace hydrogen from dilute acids

Metals react with dil. Acids to give metal chloride and hydrogen

gas1.Sodium metal reacts violently with dl. Acids

2Na +2HCl2NaCl+H22.The reaction of magnesium with dil.acids is less vigorousthan sodium ,so mg is less reactive than Na

Mg+2HClMgCl2+H23.The reaction of aluminium with dil. Acids is less rapid thanthat f Mg.so it is less reactive than Mg

2Al+6HCl2AlCl3+3H2


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Reaction of zinc granules with HCl to evolvehydrogen gas.


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1.The metals like copper and silver which are lessreactive than hydrogen do not displace hydrogenfrom dil.acids .Because they do not give outelectrons required for reaction of hydrogen ionpresent in the acids

2.Hygrogen gas is not evolved when a metalreacts with nitric acid.It is because it is a strongoxidising agent.

3.Aqua regia is a freshly prepared mixture ofconcentrated HCl and concentrated nitric acid inthe ratio of 3:1.It can even dissolve less reactivemetal like gold and platinum too.

AQUA REGIA


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A more reactive metal displaces a less reactive

metal from its salt solution. (Displacementreaction)

Magnesium displaces copper from copper

sulphate solution.

Mg + CuSO4 MgSO4 + Cu

Zinc displaces copper from copper sulphatesolution.

Zn + CuSO4 ZnSO4 + Cu

Iron displaces copper from copper sulphatesolution

Fe + CuSO4 FeSO4 + Cu


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A metal is a chemical element that is agood conductor ofboth electricity and heat and

forms cations and ionicbonds with non-metals


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ELECTRONIC CONFIGRATION: Non metalsare generally have 4,5,6,or 7 valenceelectrons.ELECTROPOSITIVE CHARACTER: Nonmetals have a tendency to gain valenceelectrons and acquire a stable noble gasconfiguration therefore, they areElectropegative in nature.

MELLAEBALITY AND DUCTILITY: Nonmetals re brittle in nature.

THERMAL AND ELECTRIC CONDUCTIVITY:Non metals are poor conductor i.e.insulators of heat and electricity.

HARDNESS: Metals are generally soft in

nature

O

X

Y

G

E

N


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Ionic compounds are compounds formed by the

transfer of electrons from a metal to a nonmetal.

Properties of ionic compounds

i) They are crystalline solids.

ii) They have high melting points and boilingpoints.

iii) They are soluble in water but insoluble inorganic solvents (like petrol, kerosene etc.)

iv) They conduct electricity in molten state or insolution.

v) They are formed by the transfer of electronsand are made up of ions.


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Some metals like gold, silver, platinum etc are found in thefree state in the earths crust because they are least reactive.Most metals are found as oxides, carbonates, sulphides,halides etc.

Minerals :- are elements or compounds which occur naturallyinside the earths crust.

Ore :- is a mineral from which metals can be extractedprofitably. Gangue :- is the impurities present in the ore likerock particles, sand particles, clay particles etc.

i) Concentration of the ore (Enrichment of the ore).

ii) ii) Reduction to the metal.

iii) iii) Refining (Purification of the metal). Concentration of the ore :- isthe removal of gangue (impurities) from the ore by different methods.

ACTIVITY SERIES AND RELATEDMETALLURGY


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The removal of impurities from the metal toobtain the pure metal is called refining of metals.The most common method for refining of metalsis electrolytic refining. In this method a block ofthe impure metal is made the anode and a thinsheet of the pure metal is made the cathode. Theelectrolyte is a salt solution of the metal to be

purified.

Eg :- In the electrolytic refining of copper, ablock of impure copper is made the anode and a

thin sheet of pure copper is made the cathode.The electrolyte is acidified copper sulphatesolution. When electric current is passedthrough the electrolyte, pure copper from theanode is deposited at the cathode and theimpurities settle down as anode mud.


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Sometimes reactive metals like Na, Ca,Al etc. are used as reducing agents toobtain metals from their oxides.

Eg :- 3MnO2 + 4Al Mn + 3Al2O3 + Heat )

The reaction between metal oxides and

aluminium is highly exothermic and themetals are obtained in molten state.Such reactions are called thermitreactions.

The reaction between iron oxide andaluminium produces molten iron. Thisreaction is used to join rail tracks,broken machine parts etc.

Fe2O3 + 2Al Al2O3 + 2Fe + Heat

THERMIT REACTIONOF RAILWAY TRACKS


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Corrosion is the damage caused to metals due to the reaction

of metals with oxygen, moisture, carbon dioxide etc. Eg :-Formation of brown coating of rust over iron. Formation ofgreen coating of basic copper carbonate over copper.Formation of black coating of silver sulphide over silver.

Corrosion of metals can be prevented by :- i) Applying oil or grease.

ii) Applying paint.

iii) By galvanisation. (Coating with zinc)

iv) By tinning. (Coating with tin)

v) By electroplating. (Coating a less reactive metal like chromium) vi) Byalloying. (Making alloys)

c) Alloy :- An alloy is a homogeneous mixture of a metal with other metals ornon metal. Eg :- Steel iron, carbon Stainless steel iron, carbon, cobalt,

nickel Brass copper, zinc


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Metals and Non Metals-10

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