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Element 53 - Iodine (I)
From
iodes
, or violet; discovered 1811; a blue-black solid which turns into a violet vapor when heated. Formerly prepared from seaweed, it is now produced from oil-well brines. Most table salt is now "iodized" to supplement the human diet; an iodine deficiency causes thyroid trouble.
Properties
Atomic Number
:
53
Atomic Weight
:
126.9045
Electron Configuration
(at ground state):
1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
4s
2
4p
6
4d
10
5s
2
5p
5
Oxidation States
(Bold most stable):
-1
, +1, +5, +7
Boiling Point
(K):
457.5
Melting Point (K):
386.7
Density
(at 300K -- g/cm
3
):
4.93
Atomic Volume (at 300K -- cm
3
/mol)
25.70
Number of stable
isotopes
:
1
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
129 -- 1.6 x 10
7
years --
beta particle
(
electron
) emission
131 -- 8.040 days --
beta particle
(
electron
) emission
Covalent Radius (Å):
1.33
Atomic Radius (Å):
1.32
First
Ionization Potential
(V):
10.451
Electronegativity
(Pauling's):
2.66
Specific Heat
Capacity (at 300K -- J g
-1
K
-1
):
0.145
Heat of Vaporization (kJ/mol):
20.9
Heat of Fusion (kJ/mol):
7.76
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
10
-11
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
0.449
Crystal Structure:
Orthorhombic
Acid
-
Base
Properties:
Very acidic