Is promethium a metal?

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

How many protons does promethium have?

Promethium has 61 protons. Its atomic number is 61, which is also the number of electrons in a neutral atom of promethium.

What group and period is promethium in?

Promethium 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 promethium?

The atomic mass of promethium is 145 u (unified atomic mass units).

Element 61

Promethium (Pm)

Lanthanide · Period 6 · f-block

Promethium (Pm) is element 61 of the periodic table, a lanthanide in period 6 (f-block) with an atomic mass of 145 and is a solid at standard conditions.

At a glance

Atomic number: 61
Symbol: Pm
Atomic mass: 145 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 4f5 5s2 5p6 6s2
Shorthand configuration: [Xe] 4f5 6s2
Electrons per shell: 2, 8, 18, 23, 8, 2
Oxidation states: +2, +3

Physical properties

Melting point: 1,315 K (1,041.85 °C)
Boiling point: 3,273 K (2,999.85 °C)
Density: 7.26 g/cm³
Phase: solid

Atomic properties

Electronegativity (Pauling): 1.13
Atomic radius: 205 pm
Covalent radius: 199 pm
First ionization energy: 540 kJ/mol
Electron affinity: 50 kJ/mol

Notable isotopes

Notable isotopes of Promethium: mass number, atomic mass, natural abundance, and stability.
Isotope	Mass	Abundance	Stability
Pm-145	144.91276	-	Half-life 17.7 years

Common uses

Nuclear batteries
Luminous paint
Thickness gauges

Discovery

Year: 1945
Discovered by: Jacob A. Marinsky, Lawrence E. Glendenin, Charles D. Coryell
Country: USA

Frequently asked questions

Is promethium a metal?: Yes. Promethium is a metal, classified as a lanthanide on the periodic table.
How many protons does promethium have?: Promethium has 61 protons. Its atomic number is 61, which is also the number of electrons in a neutral atom of promethium.
What group and period is promethium in?: Promethium 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 promethium?: The atomic mass of promethium is 145 u (unified atomic mass units).

Keep exploring

Promethium'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.