Return
to the Main CHEMystery Page.
Return
to the Periodic Table of the Elements
Element 84 - Polonium (Po)
After Poland; found in 1898 by Pierre and Marie Curie in pitchblende. The scarcest natural element, it was the first to be discovered by the Curies.
Properties
Atomic Number
:
84
Atomic Weight
:
209
Electron Configuration
(at ground state):
1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
4s
2
4p
6
4d
10
4f
14
5s
2
5p
6
5d
10
6s
2
6p
4
Oxidation States
(Bold most stable):
+4
, +2, +6
Melting Point (K):
527
Density
(at 300K -- g/cm
3
):
9.3
Atomic Volume (at 300K -- cm
3
/mol)
22.70
Number of natural
radioactive
isotopes:
7
Mass Number
(Bold naturally occurring) --
Half-Life
--
Disintigration Type
:
208 -- 2.90 years --
alpha particle
emission
209 -- 102 years --
alpha particle
emission
210
-- 22.3 years --
alpha particle
emission
Covalent Radius (Å):
1.53
Atomic Radius (Å):
1.67
First
Ionization Potential
(V):
8.42
Electronegativity
(Pauling's):
2.0
Heat of Vaporization (kJ/mol):
120
Heat of Fusion (kJ/mol):
13
Electrical Conductivity (at 293K for polycrystalline material -- 10
6
-1
cm
-1
):
0.7
Thermal Conductivity (at 300K -- W m
-1
K
-1
):
20
Crystal Structure:
Monoclinic
Acid
-
Base
Properties:
Amphoteric