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Element 14 - Silicon (Si)
From
silex
. or flint; discovered 1823; the second most abundant element--making up one-quarter of the earth's crust. Sand, largely silicon dioxide, goes into making glass and cement. Pure silicon is used in micro-electronic devices such as solar batteries to power satellite instruments.
Properties
Atomic Number
:
14
Atomic Weight
:
28.0855
Electron Configuration
(at ground state):
1s
2
2s
2
2p
6
3s
2
3p
2
Oxidation States
(Bold most stable):
-4, +2,
+4
Boiling Point
(K):
2630
Melting Point (K):
1683
Density
(at 300K -- g/cm
3
):
2.33
Atomic Volume (at 300K -- cm
3
/mol)
12.1
Number of stable
isotopes
:
3
Covalent Radius (Å):
1.11
Atomic Radius (Å):
1.32
First
Ionization Potential
(V):
8.151
Electronegativity
(Pauling's):
1.90
Specific Heat
Capacity (at 300K -- J g
-1
K
-1
):
0.70
Heat of Vaporization (kJ/mol):
359
Heat of Fusion (kJ/mol):
50.2
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
4 x 10
-4
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
148
Crystal Structure:
Cubic, face centered
Acid
-
Base
Properties:
Amphoteric