88 - Radium alkaline earth metal
Discovered by Pierre Curie in 1898
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).
Periodic table
| 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 |
Electron shells
silvery white metallic Appearance
226 u Atomic Mass
2.01k K Boiling Point
2 Group
2 Common Oxidation States
2.21 Å Covalent Radius
5.5 g/cm³ Density
9.65 kJ/mol Electron Affinity
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 Electron Configuration
[Rn] 7s2 Electron Configuration (semantic)
0.9 Electronegativity
88 Electrons
5.28 eV First Ionization Energy
509.3, 979 kJ/mol Ionization Energies
973 K Melting Point
13 Mendeleev Number
7 Number of Shells
2 Electron Valency
138 Neutrons
88 Atomic Number
15 Number of Isotopes
2 Oxidation States
7 Period
Solid Phase
88 Protons
2, 8, 18, 32, 18, 8, 2 Electron Shell Occupations