ACKNOWLEDGEMENT:
Figure
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Source of Figure
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Figure 20
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www.bbc.co.uk
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Figure 21
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socratic.org
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Figure 22
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www.gcse.com
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Figure 23
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www.bbc.co.uk
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Metallic Bonding:
Metal lattices are formed by metallic ions, closely packed
together in a periodic arrangement, surrounded by a sea of electrons. These
electrons are the valence electrons of each of the metal atom in the lattice.
Figure 20:
Property
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Reason
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Metals are good conductors of electricity
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The metallic ions are
arranged in a sea of electrons valence electrons moving randomly. When a pd
is applied, all these electron move towards the positive end of the applied
pd and cause a current across the ends of the metal. These valence electrons
make metals a good conductor of electricity.
Figure 21:
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Metals are good conductors of heat
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The metallic ions are
arranged in a sea of electrons valence electrons moving randomly. When an end
of a metal is heated, the electrons in that region heat up, gain K.E, and
collide with the surrounding ions and all the way towards the cold end of the
metal. This heat transferred by heated electrons make metals a good conductor
of heat.
Heat transfer is also
happens through ions vibration but this is significantly slower than that by
free electrons.
Figure 22:
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Metals have high melting and boiling points
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The arrangement is
periodic and the interatomic forces of attraction between the ions are very
strong. Therefore, metals have high melting and boiling points.
Note: The exception
is mercury, it is metal with a melting point of -38.83°C, and exists as
liquid at R.T.P.
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Metals are malleable and ductile
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Atoms in metals are
regularly arranged, packed together with strong interatomic forces. These
force are however, not rigid and when a large external force is applied,
these layers of ions can slide over one another to make the metal malleable
and ductile.
Malleability is the
ability of a metal to be hammered into sheets.
Figure 23:
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