OUR OWN HIGH SCHOOL, AL WARQA’A, DUBAI.
GRADE X –CHEMISTRY
TOPIC: METALS AND NON METALS
1.
Questions/ answers (pg 45- 54)
26-08-2012
--------------------------------------------------------------------------------------------------Compare the chemical properties of metals and non metals.
property
Metals
Non metals
1.Nature of ions
Metals are electropositive in
nature. That is, they lose one or
more electrons forming positive
ions.
They are
electronegative and
gain electrons
forming negative
ions
2.Nature of oxides
Form basic oxides
Non-metals form
acidic oxides or
neutral oxides
Except fluorine, nonmetals do not react
with water.
3.Reaction with water Metals displace hydrogen from
water or steam
4.Reaction with
dilute acids
Metals lying above hydrogen in
the reactivity series displace
hydrogen from dilute acids
Do not react with
dilute acids.
5.Nature of chlorides
With chlorine, metals form
chlorides which are electrovalent
6.Nature of hydrides
Highly electropositive metals form
hydrides which are electrovalent
(mostly unstable)
With chlorine, nonmetals form
chlorides which are
covalent
Non-metals form
many stable hydrides
which are covalent
2. What is meant by the reactivity series of metals?
The arrangement of metals in a vertical column in order of their decreasing reactivity
downwards is called the reactivity series of metals.
Important points:
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the metal which is higher in reactivity series is more reactive than the other.
K is the most reactive and Pt is the least reactive in the series.
the metals which are placed above hydrogen are more reactive than hydrogen and
these can displace hydrogen from its compounds like water and acids to liberate
hydrogen gas.
the metals which are placed below hydrogen are less reactive than H and these can’t
displace H from its compounds.
a more reactive metal can displace a less reactive metal from its solution
the least reactive elements such as Au and Pt exist as free elements in nature.
3 Why do elements differ in their reactivity?
The reactivity of elements differ due to the tendency to attain a completely filled valence
shell.
4
5
6
Complete the following reaction:
CuSO4 + Fe 
Mg
+ ZnCl2 -
AgCl
+ Al 
FeSO4 + Hg 
AgNO3 + Cu 
What are ionic compounds?
A chemical bond formed between two atoms by complete transference of electrons from
one atom to another so as to complete their octets and hence acquire the stable nearest
noble gas configuration is called ionic bond or electrovalent bond.
The compounds thus formed are called ionic compounds or electrovalent compounds.
eg NaCl , CaO, MgS, ZnCl2 etc
Show the electron dot structure of the formation of the following ionic compounds.
Na + Cl 
Mg + Cl2 
Ca + O 
2Na + O 
7
8
(leave space)
State the properties of ionic compounds.
Refer pg 49 --all 4 pts.
Define the following:
Minerals, ores, gangue, metallurgy.
The natural materials in which metals occur in the form of their compounds are called
minerals
Ores are minerals from which metals can be extracted profitably.
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10
11
12
The unwanted material present in the ores mined from earth is called gangue.
All the processes involved in the extraction of metals from their ores and refining
them for use, is called metallurgy
How are metals classified based on their reactivity?
(a) metals of low reactivity
(b) metals of medium reactivity
© metals of high reactivity.
What are the steps involved in the extraction of a metal from its ore.
(a) concentration of ore( enrichment of ore)
(b) conversion of concentrated ore into metal
(c) refining (purification) of impure metal.
Draw a flow chart that represent the various steps involved in the extraction
of metals from their ores.
Do fig 3.10 pg 50
Account for the following:
(a) Ionic compounds conduct electricity in molten state and not in solid state.
This is because movement of ions in the solid is not possible due to
their rigid structure. In molten state the electrostatic forces of attraction
is overcome due to heat. Thus the ions can move freely and conduct electricity.
(b) Non-metals do not react with water or steam to produce hydrogen gas.
This is because non-metals can’t give electrons to reduce the hydrogen ions
of water into hydrogen gas.
© Aluminium oxide is an amphoteric oxide.
Oxides that are acidic as well as basic in nature are called amphoteric oxides.
They react both with acids as well as bases to form salt and water. ZnO is also
an example.
(d) Aluminium is more active than iron, yet there is less erosion of aluminium when
both are exposed to air.
A thin but strong layer of aluminium oxide is formed on its surface which
protects Al atoms underneath, whereas, the rust formed on iron is a flaky
substance which falls off from its surface exposing the surface again for
rusting.
(e) Solder is used for welding electrical wires together.
Solder has a low melting point.
(f) A sulphide ore is converted into its oxide to extract the metal.
It is easier to extract a metal from its oxide by the process of reduction
than from its sulphide.
(g) Tarnished copper vessels are cleaned with tamarind juice.
Tamarind juice is acidic and neutralizes the basic layer of copper carbonate
on tarnished copper vessels.
13. Differentiate between roasting and calcination.
Roasting is a process in which ore is heated in the presence of air so as to
obtain metal oxides, which can be reduced easily to get free metal. Sulphide
ores are converted into oxides.
2ZnS(s) + 3O2 (g)
+ 2SO2(g)
-- 2ZnO(s)
Calcination is a process of heating ore in the absence of air so as to remove
moisture and volatile impurities and to convert carbonate ores into oxides.
ZnCO3
heat >
ZnO + CO2
14 Giving one example of each, explain how the following metals are extracted
from their compounds .
(a) Metal ‘A’ which is low in the activity series of metals.
(b) Metal’B’ which is in the middle of the activity series of metals.
(c) Metal’C’ which is high in the activity series of metals.
Metal ‘A’ in the low activity is very unreactive. The sulphide ore is heated
in air , it is converted into its oxide which can be reduced on further heating
eg. 2 HgS
2HgO
+ 3 O2  2 HgO + 2 SO2
(heat)  2Hg + O2
Metal’ B ‘ is moderately reactive. It usually exists as sulphides or carbonates.
The sulphide ore is converted into its oxide by heating strongly in the
presence of excess air(roasting).
2ZnS + 3O2  2ZnO + 2SO2
If it is a carbonate ore, it has to undergo the process of calcination.
ZnCO3 - ZnO + CO2
The metallic oxide thus obtained is reduced by heating it with carbon.
ZnO + C  Zn + CO
Metal ‘C’is very reactive. This metal can be obtained by electrolytic reduction.
By electrolysis of its molten chloride, the metal is deposited at the cathode
whereas, chlorine is liberated at the anode.
eg. At cathode Na+ + e-  Na
at anode 2Cl Cl2 + 2e15. What is meant by refining of metals? In the electrolytic refining of metal’X’
name the cathode, anode and the electrolyte.
The process of purifying impure (crude) metals is called refining of the metals.
Cathode: pure metal –X
Anode : impure ‘X’
Electrolyte: a clear solution of X
Electrolytic refining of copper –draw the diag. 3.12 on pg 52
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