Periodic table / Thulium

Overview

Thulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate (third-last) element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.

Electron configuration

The electron configuration of Thulium is [Xe] 4f13 6s2, with electron shells of 2, 8, 18, 31, 8, 2.

Physical and chemical properties

Thulium is classified as a lanthanide. It has an atomic mass of 168.934 and exists as a solid at standard conditions, appearing as silvery gray.

Real-world uses of Thulium

Thulium, a lanthanide, is used in magnets, electronics, lighting, and other specialized high-tech applications.

Interesting facts about Thulium

• Thulium has the atomic number 69 and chemical symbol Tm.
• It belongs to period 6, group 3 of the periodic table.
• Thulium was discovered by Per Teodor Cleve.

Explore Thulium interactively

Want to compare Thulium with other elements or see it highlighted on the full table? Open the interactive periodic table and click on Tm to explore properties, trends, and neighboring elements. You can also test your knowledge with our periodic table quiz game.