88 · Ra
Radium
Announced by Pierre and Marie Curie in December 1898.
Identity
- Atomic number
- 88
- Symbol
- Ra
- Canonical name
- Radium
- Category
- alkaline earth metal
- Group
- 2
- Period
- 7
- Block
- s
Properties
These quantities come from the Periodic Table JSON compilation. They have not yet been checked, one by one, against CIAAW atomic weights or NIST measurements. A value marked estimated is not a measurement.
- Atomic mass
- [226] No standard atomic weight. The number shown is the conventional mass number used in tables, not a measured mass in u.
- Electron configuration
- [Rn] 7s2
- Electrons per shell
- 2, 8, 18, 32, 18, 8, 2
- Standard state
- solid
- Density
- 5.5 g/cm³
- Melting point
- 1,233 K
- Boiling point
- 2,010 K
- Electronegativity
- 0.9 Pauling
- First ionization energy
- 509.3 kJ/mol
- Electron affinity
- 9.6485 kJ/mol
Notable isotopes
This summary is not an inventory of every isotope.
Conventional mass number: 226
History
Radium
Discovery · jointly credited · 1898
The Curies announce radium in December 1898. Isolation of weighable salts comes in the following years.
Etymology
- Theme
- property
- Language
- latin
- Root
- radius
- Meaning
- ray
Scientists
Places and institutions
- Paris — historical setting : France — present country : France
See also
Sources
- IUPAC, Periodic Table of the Elements
- Bowserinator, Periodic Table JSON. Compilation secondaire d’où viennent les grandeurs physiques importées (masse, densité, températures, énergies). Elles ne sont pas revérifiées une à une auprès du NIST ou de la CIAAW.
- Pierre et Marie Curie, notes aux Comptes rendus de l’Académie des sciences, 1898
- John Emsley, Nature’s Building Blocks: An A–Z Guide to the Elements