• Elementscanbeclassifiedasmetalsandnon-metalsonthebasisoftheirproperties.
• Exampleofsomemetalsare:
Iron(Fe),Aluminium(Al),Silver(Ag),Copper(Cu)
• Examplesofsomenon-metalsare:
Hydrogen(H),Nitrogen(N),Sulphur(S),Oxygen(O)
I. PHYSICAL PROPERTIES
PROPERTY
METALS
NON-METALS
1.Lustre
Metalshaveshiningsurface.
They do not have shining
surface.
•ExceptIodine.
2.Hardness
Theyaregenerallyhard.
•ExceptSodium,LithiumandPotassium
which are soft and can be cut with
knife.
Generallysoft.
• Except Diamond, a form
of carbon which is the
hardestnaturalsubstance.
3.State
Existassolids.
•ExceptMercury.
Existassolidsorgaseous.
•ExceptBromine.
4.Malleability
Metalscanbebeatenintothinsheets.
Non-metals
•GoldandSilverarethemostmalleable malleable.
metals.
5.Ductility
Metalscanbedrawnintothinwires.
are
non-
Theyarenon-ductile.
6.Conductorof Metalsaregoodconductorsofheatand Non-metals
are
poor
heat&elecelectricity.
conductor of heat and
tricity
• Silver (Ag) and Copper (Cu) : Best electricity.
conductorsofheat.
•ExceptGraphite.
• Lead (Pb), Mercury (Hg) poor
conductorofheat.
7.Density
Generally have high density and high Have low density and low
meltingpoint.
meltingpoint.
•ExceptSodiumandPotassium.
8.Sonorous
Metals produce a sound on striking a Theyarenotsonorous.
hardsurface.
9.Oxides
Metallicoxidesarebasicinnature.
Non-metallic oxides are
II. CHEMICAL PROPERTIES OF METALS
(A) Reaction with Air :
Metalscombinewithoxygentoformmetaloxide.
Metal+O2 →Metaloxide
Examples :
(i)
2Cu+O2 →2CuO
Copper oxide (black)
(ii)
4Al+3O2 →2Al2O3
Aluminiumoxide
(iii) 2Mg+O2 →2MgO
DifferentmetalsshowdifferentreactivitiestowardsO2.
•
NaandKreactsovigorouslythattheycatchfireifkeptinopensotheyarekept
immersedinkerosene.
•
SurfacesofMg,Al,Zn,Pbarecoveredwithathinlayerofoxidewhichprevent
themfromfurtheroxidation.
•
Fedoesnotburnonheatingbutironfillingsburnvigorously.
•
Cudoesnotburnbutiscoatedwithblackcopper oxide.
•
AuandAgdoesnotreactwithoxygen.
Amphoteric Oxides : Metaloxideswhichreactwithbothacidsaswellasbasesto
producesaltsandwaterarecalledamphotericoxides.
Examples:Al2O3+6HCl→2AlCl3 + H2O
Al2O3+2NaOH→2NaAlO2 + H2O
SodiumAluminate
(B) Reaction of Metals with Water :
Metal+Water→Metaloxide+Hydrogen
Metaloxide+Water→Metalhydroxide
Reactwithsteam Al,Fe,Zn ReactwithcoldH2O
Na,K,Ca
ReactwithhotH2O
Mg
Metals
NoreactionwithH2O
Pb,Cu,Au,Ag Examples
:
(i) 2Na+2H2O→2NaOH+H2 + Heat
(ii)Ca+2H2O→Ca(OH) 2 + H2
CaandMgfloatas
bubblesofH2
sticktotheirsurface
(iii)Mg+2H2O→Mg(OH)2 + H2
(iv)2Al+3H2O→Al2O3 + 3H2
(v)3Fe+4H2O→Fe3O4 + 4H2
(C) Reaction of Metals with Acids (Dilute) :
Metal+Diluteacid→Salt+H2
Cu,Ag,Hgdonotreactwithdil.acids.
Examples :
(i) Fe+2HCl→FeCl + H
2
2
(ii)Mg+2HCl→MgCl2 + H2
(iii)Zn+2HCl→ZnCl2 + H2
(iv)2Al+6HCl→2AlCl3 + 3H2
(D) Reaction of Metals with Solutions of other Metal Salts :
MetalA+SaltsolutionB→SaltsolutionA+MetalB
• Reactivemetalscandisplacelessreactivemetalsfromtheircompoundsinsolution
form. Fe + CuSO4 → FeSO4 + Cu
REACTIVITY SERIES
Thereactivityseriesisalistofmetalsarrangedintheorderoftheirdecreasingactivities.
K
Na
Ca
Mg
Al
Zn
Fe
Pb
Mostreactive
Reactivitydecreases
H
Cu
Hg
Ag
Au
Leastreactive
Reaction of Metals with Non-metals
• Reactivityofelementsisthetendencytoattainacompletelyfilledvalenceshell.
• Atomsofthemetalsloseelectronsfromtheirvalenceshelltoformcation.Atomof
thenon-metalsgainelectronsinthevalenceshelltoformanion.
E.g., FormationofNaCl
Na→Na+ + e-
2,8,1 2,8
Sodiumcation
Cl+e− → Cl-
2,8,7 2,8,8
Chlorideanion
Ionic Compounds
Thecompoundsformedbythetransferofelectronsfromametaltoanon-metalare
calledioniccompoundsorelectrovalentcompounds.
Properties of Ionic Compounds
1. Physical nature : Thearesolidandhard,generallybrittle.
2. Melting and Boiling Point : Theyhavehighmeltingandboilingpoint.
3. Solubility : Generallysolubleinwaterandinsolubleinsolventssuchaskerosene,
petroletc.
4. Conduction of electricity : Ionic compounds conduct electricity in molten and
solutionformbutnotinsolidstate.
Occurrence of Metals
Minerals : Theelementsorcompoundswhichoccurnaturallyintheearth’scrustare
calledminerals.
Ores : Mineralsthatcontainveryhighpercentageofparticularmetalandthemetal
canbeprofitablyextractedfromit,suchmineralsarecalledores.
reactivemetals Ca
Notfoundinfreestate
byelectrolysis
reactive Pb
Occurassulphides,oxides,carbonates
byusingcarbon
g
reactive Au
Occurinnative/freestate
Extraction of Metals from Ores
Step 1. Enrichmentofores.
Step 2. Extractionofmetals.
Step 3. Refiningofmetals.
ORE
Concentrationofore
Metalswithhigh
Metalsofmedium
Metalsoflow
reactivity
reactivity
reactivity
Sulphideores
Electrolysisofmoltenore
Carbonateore
Sulphideore
e.g.,ZnCO3
e.g.,HgS(cinnabar),ZnS
(inlimitedair) (excessair)
PureMetal
Calcination
Roasting
Oxidesofmetal
Reductiontometal
Metal
Purificationofmetal
Refining
Roasting
Steps Involved in Extraction of Metals from Ores
Some Important Terms
(a) Gangue : Oresareusuallycontaminatedwithlargeamountofimpuritiessuchassoil,
sandetc.calledgangue.
(b) Roasting : The sulphide ores are converted into oxides by heating strongly in the
presenceofexcessair.Thisprocessiscalledroasting.
2ZnS+3O2
Heat
→
2ZnO+2SO2
(c) Calcination : Thecarbonateoresarechangedintooxides byheatingstronglyinlimited
air.Thisprocessiscalledcalcination.
ZnCO3
Heat
→
ZnO+CO2
(d) Reduction : Metaloxidesarereducedtocorrespondingmetalsbyusingreducingagent
likecarbon. ZnO+C→Zn+CO
Refining of Metals
Themostwidelyusedmethodforrefiningimpuremetaliselectrolyticrefining.
•Anode:Impurecopper
•Cathode:Stripofpurecopper
•Electrolyte:Solutionofacidifiedcoppersulphate
(a)Onpassingthecurrentthroughelectrolyte,theimpuremetalfromanodedissolvesinto
theelectrolyte.
(b)Anequivalentamountofpuremetalfromtheelectrolyteisdepositedatthecathode.
(c)Theinsolubleimpuritiessettledownatthebottomoftheanodeandiscalledanode
mud.
Corrosion
Thesurfaceofsomemetalssuchasironiscorrodedwhentheyareexposedtomoistair
foralongperiodoftime.Thisiscalledcorrosion.
(i) Silverbecomesblackwhenexposedtoairasitreactswithairtoformacoatingof
silversulphide.
(ii)Copperreactswithmoistcarbondioxideintheairandgainsagreencoatofcopper
carbonate.
(iii)Ironwhenexposedtomoistairacquiresacoatingofabrownflakysubstancecalled
rust.
Prevention of Corrosion
Therustingofironcanbepreventedbypainting,oiling,greasing,galvanizing,chrome
plating,anodizingormakingalloys.
Galvanization : Itisamethodofprotectingsteelandironfromrustingbycoatingthem
withathinlayerofzinc.
Alloy : Analloyisahomogenousmixtureoftwoormoremetalsorametalandanonmetal.
Iron :Mixedwithsmallamountofcarbonbecomeshardandstrong.
Steel : Iron+Nickelandchromium
Brass : Copper+Zinc
Bronze : Copper+Tin(Sn)
Solder : Lead+tin
Amalgam : Ifoneofthemetalis mercury(Hg).
QUESTIONS
1. Whatisthedifferencebetweenamineralandanore?
2. Differentiatebetweenroastingandcalcinationsprocessinmetallurgy.
3. What is an alloy ? Name the alloy which has iron, nickel and chromium as its
constituent.Whatisthechiefuseofthisalloy?
4. Explainanytwowaystopreventrustingofiron.
Hints To Questions
1. 2. Mineral
Naturaloccurringchemical
substancesobtainedbymining
Roasting
(a)Oreisheatedinthe
presenceofair.
(b)Convert
Ore
Anoreisamineralfrom whichmetalisobtained.
Calcination
(a) Oreisheatedin
absenceofair.
(b) Convert
→ Oxideore
Sulphideore → OxideoreCarbonateore 
Roasting
Calcination
3. Alloy : Itisahomogenoussolidsolutionofonemetalwithoneormoremetalsornonmetals.
Stainlesssteel,usedformakingutensils,equipments.
4. (a) Bycoatingthesurfacewithathinfilmofoilorgrease.
(b)Bypaintingthesurface.
(c) Bytheprocessofgalvanization.