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Element 95 - Americium (Am)
Named after the Americas, by analogy with the rare earth Europium; discovered 1944. Americium is produced by bombarding plutonium with neutrons. It has been made in gram quantities which, in the world of such elements, is virtually a superabundance.
Properties
Atomic Number
:
95
Atomic Weight
:
(243)
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
7
6s
2
6p
6
7s
2
Oxidation States
(Bold most stable):
+6, +5, +4,
+3
Boiling Point
(K):
2880
Melting Point (K):
1449
Density
(at 300K -- g/cm
3
):
13.7
Atomic Volume (at 300K -- cm
3
/mol)
20.8
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
241 -- 432 years --
alpha particle
emission
243 -- 7.37 x 10
3
years --
alpha particle
emission
Atomic Radius (Å):
1.84
First
Ionization Potential
(V):
6.0
Electronegativity
(Pauling's):
1.3
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
0.7
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
10
Crystal Structure:
Hexagonal
Acid
-
Base
Properties:
Amphoteric