- Atomic Radius (Å)
Radium is a chemical element with symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is almost colorless, but it readily combines with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride (Ra3N2).
88
Atomic Number
226 u
Atomic Mass
973.15 K
Melting Point
2010 K
Boiling Point
5.5 g/cm³
Density
null Å
Atomic Radius
2.21 Å
Covalent Radius
0.9
Electronegativity
5.28 eV
First Ionization Energy
9.65
Electron Affinity
7
Number of Shells
2
Electron Valency
2, 8, 18, 32, 18, 8, 2
Electron Shell Occupations
null J/g
Specific Heat