Thorium (Th), element 90 – Learn Acer periodic table

Thorium

Actinide, atomic number 90.

Thorium is a chemical element with symbol Th and atomic number 90. A radioactive actinide metal, thorium is one of only two significantly radioactive elements that still occur naturally in large quantities as a primordial element (the other being uranium). It was discovered in 1828 by the Norwegian Reverend and amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jakob Berzelius, who named it after Thor, the Norse god of thunder.

Facts

Symbol Th. Atomic mass 232.03774 u. Group 3, period 7. Electron configuration [Rn] 6d2 7s2. Electrons per shell 2, 8, 18, 32, 18, 10, 2. State at room temperature: Solid. Melting point 1749.8 °C, boiling point 4787.9 °C. Discovered by Jöns Jakob Berzelius.

Element data from Wikipedia, CC BY-SA 3.0.