Basic Information
Name
Radium
Atomic Number
88
Appearance
Silvery white metallic
Phase At STP
Solid
Spectrum Image
Source
WikipediaBohr Model
Static
Interactive
Descriptive Numbers
CAS Number
7440-14-4
CID Number
CID6328144
Mendeleev Number
10
Pettifor Number
13
Eu Number
Joa 1-122-4
Space Group Number
229
Glawe Number
13
Mass
Atomic Mass
226 Da
Periodic Position
X Position
2
Y Position
7
Period
7
Group
2
Classification
Block
s
Category
Alkaline Earth Metal
Geochemical
U/Th decay series
Goldschmidt
Lithophilic
Electrical Type
Conductive
Abundance
Seawater
8.9e-17 kg/L
Earth Crust
9e-13 g
Human Body
1e-13 %
Meteorites
N/A %
Color
Jmol
#007D00
Molcas Gv
#007D00
CPK
#FFFFFF
Atomic Radius
Empirical
215
Van Der Waals
283
Rahm
292
Uff
367.7
Mm3
327
Truhlar
283
Covalent (Triple Bound)
159
Covalent (Cordero)
221
Covalent (Pyykko)
201
Covalent (Pyykko Double)
173
Covalent (Pyykko Triple)
159
Temperature
Melting/Freeze (USE)
1233 °K
Melting/Freeze (WEL)
973 °K
Melting/Freeze (CRC)
973 °K
Melting/Freeze (LNG)
973.1 °K
Boiling/Density (USE)
2010 °K
Boiling/Density (WEL)
2010 °K
Boiling/Density (LNG)
2010 °K
Density
STP
5.5 kg/cm³
Solid (WEL)
5000 kg/cm³
Solid (CRC)
5000 kg/cm³
Solid (LNG)
5500 kg/cm³
Heat
Molar Volume
41.09 cm³/mol
Atomic Volume
45 cm³
Heat Of Fusion USE
9.6 kJ/mol
Evaporation USE
113 kJ/mol
Heat Capacity USE
0.12 J/gK
Adiabatic Index
N/A
Electrical Resistance
293k
1000 nΩm
Etymology
Description
It is a transuranic radioactive metal element in the second group. Ra-226, the most stable isotope that decays to radon, has a half-life of 1602 years. It was isolated from uraninite by Marie and Pierre Curie in 1898.
Language Of Origin
Latin via French
Origin Of Word
From Latin radius meaning "ray"
Meaning
ray
Symbol Origin
descriptive
Etymological Description
From Latin radius meaning "ray". It was given this name because of its radioactivity.
Discovery & Isolation
Observed/Predicted By
Perrie ve Marie Curie
Observed/Discovery Year
1898
Discovery Location
Isolated Sample By
M. Curie
Isolated Sample Year
1902
Production & Use
Sources
It is found in uranium ores at a ratio of 1/3 ppm to uranium.
Uses
It is used in cancer treatment due to the gamma rays it emits.
Radioactivity
Half Life
1.59×10^3 years
Lifetime
2.31×10^3 years
Decay Mode
Alpha Six
Neutron Cross Section
20
Electron Affinity
Electron Affinity (eV)
0.1
Electron Affinity (kJ/mol)
9.6485
Electron Affinity (pauling)
0.9
Electron Affinity (ghosh)
0.09789
Dipole Polarity
Accepted
246
Uncertainty
4
Lattice
Angles
p/2, p/2, p/2
Electron & Quantum
Oxidation States
2
Electron Configuration
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2
Quantum Number
1S0
Electron Configuration Semantic
[Rn] 7s2
Shells-0
2
Shells-1
8
Shells-2
18
Shells-3
32
Shells-4
18
Shells-5
8
Shells-6
2
Ionization Energies-0
509.3
Ionization Energies-1
979
