Thorium (Th)
Thorium (Th) is element 90 of the periodic table, an actinide in period 7, in the f-block. Its standard atomic weight is 232.0377, so one mole of thorium atoms has a mass of 232.0377 g. At room temperature it is a solid; it melts at 1749.85 °C and boils at 4787.85 °C.
| Atomic number | 90 |
|---|---|
| Symbol | Th |
| Standard atomic weight | 232.0377 |
| Molar mass | 232.0377 g/mol |
| Category | Actinide |
| Group | f-block (actinide series) |
| Period | 7 |
| Block | f-block |
| Electron configuration | [Rn] 7s2 6d2 |
| Oxidation states | +4 |
| Electronegativity (Pauling) | 1.3 |
| Atomic radius (van der Waals) | 237 pm |
| First ionisation energy | 6.08 eV (586.6 kJ/mol) |
| Electron affinity | — |
| State at room temperature | Solid |
| Melting point | 2023 K (1749.85 °C) |
| Boiling point | 5061 K (4787.85 °C) |
| Density | 11.72 g/cm³ |
| Discovered | 1828 |
Actinides
Ac · ActiniumPa · ProtactiniumU · UraniumNp · NeptuniumPu · PlutoniumAm · AmericiumCm · CuriumBk · BerkeliumCf · CaliforniumEs · EinsteiniumFm · FermiumMd · MendeleviumNo · Nobelium
Calculate with Thorium
Atomic weight: IUPAC CIAAW standard atomic weight. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.