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

How many protons does terbium have?

Terbium has 65 protons. Its atomic number is 65, which is also the number of electrons in a neutral atom of terbium.

What group and period is terbium in?

Terbium 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 terbium?

The atomic mass of terbium is 158.93 u (unified atomic mass units).

Element 65

Terbium (Tb)

Lanthanide · Period 6 · f-block

Terbium (Tb) is element 65 of the periodic table, a lanthanide in period 6 (f-block) with an atomic mass of 158.93 and is a solid at standard conditions.

At a glance

Atomic number: 65
Symbol: Tb
Atomic mass: 158.93 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 4f9 5s2 5p6 6s2
Shorthand configuration: [Xe] 4f9 6s2
Electrons per shell: 2, 8, 18, 27, 8, 2
Oxidation states: +1, +2, +3, +4

Physical properties

Melting point: 1,629 K (1,355.85 °C)
Boiling point: 3,503 K (3,229.85 °C)
Density: 8.229 g/cm³
Phase: solid

Atomic properties

Electronegativity (Pauling): 1.2
Atomic radius: 225 pm
Covalent radius: 194 pm
First ionization energy: 566 kJ/mol
Electron affinity: 50 kJ/mol

Notable isotopes

Notable isotopes of Terbium: mass number, atomic mass, natural abundance, and stability.
Isotope	Mass	Abundance	Stability
Tb-159	158.92535	100%	Stable

Common uses

Fluorescent lamps
Magnets
Lasers
X-ray screens

Discovery

Year: 1843
Discovered by: Carl Gustaf Mosander
Country: Sweden

Frequently asked questions

Is terbium a metal?: Yes. Terbium is a metal, classified as a lanthanide on the periodic table.
How many protons does terbium have?: Terbium has 65 protons. Its atomic number is 65, which is also the number of electrons in a neutral atom of terbium.
What group and period is terbium in?: Terbium 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 terbium?: The atomic mass of terbium is 158.93 u (unified atomic mass units).

Keep exploring

Terbium'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.