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Element 92 - Uranium (U)
After the planet Uranus; discovered 1789; the heaviest atom among the natural elements. Its most common form has a half-life of 4.5 billion years. Uranium is used in a nuclear reactor to generate neutrons to keep the chain reaction going.
Properties
Atomic Number
:
92
Atomic Weight
:
238.029
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
6
4f
14
5d
10
5f
3
6s
2
6p
6
6d
1
7s
2
Oxidation States
(Bold most stable):
+6
, +5, +4, +3
Boiling Point
(K):
4407
Melting Point (K):
1408
Density
(at 300K -- g/cm
3
):
18.95
Atomic Volume (at 300K -- cm
3
/mol)
12.50
Number of natural
radioactive
isotopes:
3
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
233 -- 1.59 x 10
5
years --
alpha particle
emission
234
-- 2.44 x 10
5
years --
alpha particle
emission
235
-- 7.04 x 10
8
years --
alpha particle
emission
236 -- 2.34 x 10
7
years --
alpha particle
emission
237
-- 4.47 x 10
9
years --
alpha particle
emission
Covalent Radius (Å):
1.42
Atomic Radius (Å):
1.38
First
Ionization Potential
(V):
6.05
Electronegativity
(Pauling's):
1.38
Specific Heat
Capacity (at 300K -- J g
-1
K
-1
):
0.12
Heat of Vaporization (kJ/mol):
522.58
Heat of Fusion (kJ/mol):
15.48
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
3.6
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
27.6
Crystal Structure:
Orthorhombic
Acid
-
Base
Properties:
Amphoteric