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94. Plutonium 96. Curium

95Am[243]

Americium

Actinides

Heavy, radioactive metals. Most of them are made only in laboratories.

[Rn] 5f⁷ 7s²

Atomic number: 95
Atomic mass: [243]
Protons: 95
Neutrons: 148
Electrons: 95
Shells: 2, 8, 18, 32, 25, 8, 2
State at 25 °C: Solid
Position: Period 7, f-block

Proton (+)Neutron (0)Electron (−)

Discovered byGlenn Seaborg's team, 1944Albert Ghiorso: 12 elements Glenn T. Seaborg: 10 elements

Named after the Americas, just as europium is named after Europe.

Did you know?

Most home smoke detectors contain a tiny speck of americium-241.
It gives off alpha particles, which let the detector sense smoke.

Where it's found

Made in nuclear reactors

What it's used for

Smoke detectors

Try it

There's no safe home experiment for Americium. Explore it with the animated atom above instead.