Yes. Thulium is a metal, classified as a lanthanide on the periodic table.

How many protons does thulium have?

Thulium has 69 protons. Its atomic number is 69, which is also the number of electrons in a neutral atom of thulium.

What group and period is thulium in?

Thulium is in period 6 of the periodic table. As a lanthanide in the f-block, it sits in a separate row below the main table and has no standard group number.

What is the atomic mass of thulium?

The atomic mass of thulium is 168.93 u (unified atomic mass units).

Element 69

Thulium (Tm)

Lanthanide · Period 6 · f-block

Thulium (Tm) is element 69 of the periodic table, a lanthanide in period 6 (f-block) with an atomic mass of 168.93 and is a solid at standard conditions.

At a glance

Atomic number: 69
Symbol: Tm
Atomic mass: 168.93 u
Category: Lanthanides
Period: 6
Block: f-block
Phase at STP: solid

Electron structure

Electron configuration: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f13 5s2 5p6 6s2
Shorthand configuration: [Xe] 4f13 6s2
Electrons per shell: 2, 8, 18, 31, 8, 2
Oxidation states: +2, +3

Physical properties

Melting point: 1,818 K (1,544.85 °C)
Boiling point: 2,223 K (1,949.85 °C)
Density: 9.321 g/cm³
Phase: solid

Atomic properties

Electronegativity (Pauling): 1.25
Atomic radius: 222 pm
Covalent radius: 190 pm
First ionization energy: 597 kJ/mol
Electron affinity: 50 kJ/mol

Notable isotopes

Notable isotopes of Thulium: mass number, atomic mass, natural abundance, and stability.
Isotope	Mass	Abundance	Stability
Tm-169	168.93422	100%	Stable

Common uses

Portable X-ray devices
Lasers
Superconductors
Ceramics

Discovery

Year: 1879
Discovered by: Per Teodor Cleve
Country: Sweden

Frequently asked questions

Is thulium a metal?: Yes. Thulium is a metal, classified as a lanthanide on the periodic table.
How many protons does thulium have?: Thulium has 69 protons. Its atomic number is 69, which is also the number of electrons in a neutral atom of thulium.
What group and period is thulium in?: Thulium is in period 6 of the periodic table. As a lanthanide in the f-block, it sits in a separate row below the main table and has no standard group number.
What is the atomic mass of thulium?: The atomic mass of thulium is 168.93 u (unified atomic mass units).

Keep exploring

Thulium's row is on the printable element property sheet, and its tile is on the periodic table wall chart - the same numbers as above, laid out for A4 or A3 paper.