Thulium is element number 69, with the symbol Tm. Its name comes from Thule, an old name for Scandinavia.
Atomic number 69168.9
TmThuliumツリウム (tsuriumu)
Symbol
Tm
Atomic weight
168.9
Place in the table
Period 6 · Lanthanoids
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
An old name for the north
Thulium was discovered in 1879, together with holmium. Its name comes from Thule, an old name for Scandinavia.
Where it sits on the table
The fifteen elements from lanthanum to lutetium are called the lanthanoids. On the Room of the Elements table they are in the upper of the two rows set apart at the bottom.
Think about it
Q1Scandium and thulium are both named for Scandinavia. Why might one region give two names?
Q2Why use an old name?
Q3Where is Scandinavia on a map?
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — Element names linked to Scandinavia: scandium (Scandinavia) and thulium (Thule). Counting those linked to Sweden, there are many more.