90Th232.04
Thorium
Actinide · element 90 · f-block (shown below the main table)
Quick facts
| Symbol | Th |
|---|---|
| Atomic number | 90 |
| Relative atomic mass | 232.04 |
| Category | Actinide |
| Position | f-block (shown below the main table) |
| State at 20 °C | Solid |
| Melting point | 1,750 °C |
| Boiling point | 4,788 °C |
| Density | 11.72 g/cm³ |
| Electronegativity | 1.3 |
| Electron configuration | [Rn] 6d2 7s2 |
About Thorium
Thorium has the symbol Th and atomic number 90, which means every thorium atom has 90 protons in its nucleus and, in a neutral atom, 90 electrons. At room temperature it is a solid.
Actinides are the second row of the f-block. They are all radioactive, and only a few (like uranium and thorium) occur naturally in large amounts.
It melts at 1,750 °C and boils at 4,788 °C.
Explore it
See where thorium sits, and drag the temperature slider to watch it melt and boil, on the interactive periodic table. Practise with quizzes on OmniEx.