88 - Radium alkaline earth metal
Discovered by Pierre Curie in 1898
- 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).
Shell | Electrons | Orbitals |
---|---|---|
1 | 2 | 2 in 1s |
2 | 8 | 2 in 2s + 6 in 2p |
3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
4 | 32 | 2 in 4s + 6 in 4p + 10 in 4d + 14 in 4f |
5 | 18 | 2 in 5s + 6 in 5p + 10 in 5d |
6 | 8 | 2 in 6s + 6 in 6p |
7 | 2 | 2 in 7s |
226 u
Atomic Mass
2010 K
Boiling Point
2.21 Å
Covalent Radius
5.5 g/cm³
Density
9.65
Electron Affinity
0.9
Electronegativity
5.28 eV
First Ionization Energy
973.15 K
Melting Point
7
Number of Shells
2
Electron Valency
88
Atomic Number
2, 8, 18, 32, 18, 8, 2
Electron Shell Occupations