1.4 Covalent Network Elements

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1.4 Covalent Network Elements
Diamond Structure

• LO I understand how the structure of diamond
  relates to its properties

2
The carbon atoms in diamond are held together by
bonds.
covalent
In diamond, each carbon atom is joined to
neighbouring atoms forming a huge 3D lattice.
four
hard
Diamond is very due to these strong
covalent bonds between every atom.
Diamond is used to and for making
.
cut glass
rock-boring drills
3
Networks and Melting Points

• LO I understand the relationship between network
  structures and their melting and boiling points.

4
, carbon and are all covalent
network elements.
Boron
silicon
They all have strong covalent bonds between each
atom.




2300
3642
1410
To melt these elements, strong covalent bonds
have to be .
broken
energy
A lot of is needed so the melting point
is very high.
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Graphite Structure
LO I understand how the structure of graphite
relates to its properties
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A carbon atom has bonding
electrons(valency 4)
four
In graphite, each carbon atom is bonded to just
neighbouring atoms using up only of
these electrons.
three
three
This leaves bonding electron spare.
one
delocalised
This spare electron is and gives
rise to the , conductivity of graphite.
electrical
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The carbon atoms form layers of flat
rings.
hexagonal
Weak forces hold the layers
together.
Van der Waals
As a result, the layers are able to
each other very easily
slip past
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Uses of graphite
The conduction properties of graphite make it
useful as

• electrodes

• electrical contacts in motors

The slippery properties of graphite make it
useful as

• lead in pencils

• a solid lubricant