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Element 87 - Francium (Fr)
From France; discovered 1939. A short-lived product of the decay of actinium. It was discovered by Marguerite Perey, a one-time assistant to Marie Curie.
Properties
Atomic Number
:
87
Atomic Weight
:
(223)
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
6s
2
6p
6
7s
1
Oxidation States
(Bold most stable):
+1
Boiling Point
(K):
950
Melting Point (K):
300
Number of natural
radioactive
isotopes:
1
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
212 -- 19.3 minutes -- orbital
electron capture
,
alpha particle
emission
222 -- 15 minutes --
beta particle
(
electron
) emission
223
-- 21.8 minutes --
beta particle
(
electron
) emission
Atomic Radius (Å):
2.7
Electronegativity
(Pauling's):
0.7
Heat of Vaporization (kJ/mol):
64
Heat of Fusion (kJ/mol):
2.1
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
15
Crystal Structure:
Cubic, body centered
Acid
-
Base
Properties:
Very basic