90 · Th
Thorium
Identified by Berzelius in 1829.
Identity
- Atomic number
- 90
- Symbol
- Th
- Canonical name
- Thorium
- Category
- actinide
- Group
- unassigned
- Period
- 7
- Block
- f
Series set apart from the main table. Whether group 3 is lanthanum or lutetium (actinium or lawrencium) is still discussed, so the group is left empty.
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
- 232.03774 u
- Electron configuration
- [Rn] 6d2 7s2
- Electrons per shell
- 2, 8, 18, 32, 18, 10, 2
- Standard state
- solid
- Density
- 11.724 g/cm³
- Melting point
- 2,023 K
- Boiling point
- 5,061 K
- Electronegativity
- 1.3 Pauling
- First ionization energy
- 587 kJ/mol
- Electron affinity
- 112.72 kJ/mol
History
Thoria
Discovery · confirmed · 1829
Berzelius identifies thorium in a Norwegian mineral.
Etymology
- Theme
- mythology
- Language
- norrois
- Root
- Thor
- Meaning
- Thor
Scientists
Places and institutions
- Stockholm — historical setting : Sweden — present country : Sweden
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.
- John Emsley, Nature’s Building Blocks: An A–Z Guide to the Elements