Is americium a metal?

Yes. Americium is a metal, classified as an actinide on the periodic table.

How many protons does americium have?

Americium has 95 protons. Its atomic number is 95, which is also the number of electrons in a neutral atom of americium.

What group and period is americium in?

Americium is in period 7 of the periodic table. As an actinide 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 americium?

The atomic mass of americium is 243 u (unified atomic mass units).

Element 95

Americium (Am)

Actinide · Period 7 · f-block

Americium (Am) is element 95 of the periodic table, an actinide in period 7 (f-block) with an atomic mass of 243 and is a solid at standard conditions.

At a glance

Atomic number: 95
Symbol: Am
Atomic mass: 243 u
Category: Actinides
Period: 7
Block: f-block
Phase at STP: solid

Electron structure

Electron configuration: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6 5f7 7s2
Shorthand configuration: [Rn] 5f7 7s2
Electrons per shell: 2, 8, 18, 32, 25, 8, 2
Oxidation states: +2, +3, +4, +5, +6, +7

Physical properties

Melting point: 1,449 K (1,175.85 °C)
Boiling point: 2,880 K (2,606.85 °C)
Density: 13.69 g/cm³
Phase: solid

Atomic properties

Electronegativity (Pauling): 1.3
Atomic radius: 173 pm
Covalent radius: 180 pm
First ionization energy: 578 kJ/mol
Electron affinity: 10 kJ/mol

Notable isotopes

Notable isotopes of Americium: mass number, atomic mass, natural abundance, and stability.
Isotope	Mass	Abundance	Stability
Am-243	243.06138	-	Half-life 7370 years

Common uses

Smoke detectors
Neutron sources
Space missions

Discovery

Year: 1944
Discovered by: Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, Albert Ghiorso
Country: USA

Frequently asked questions

Is americium a metal?: Yes. Americium is a metal, classified as an actinide on the periodic table.
How many protons does americium have?: Americium has 95 protons. Its atomic number is 95, which is also the number of electrons in a neutral atom of americium.
What group and period is americium in?: Americium is in period 7 of the periodic table. As an actinide 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 americium?: The atomic mass of americium is 243 u (unified atomic mass units).

Keep exploring

Americium'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.