Americium (Am)

Americium is a radioactive chemical element with symbol Am and atomic number 95. This transuranic element of the actinide series is located in the periodic table under the lanthanide element europium, and thus by analogy was named after the Americas.

Atomic Number

95

Atomic Mass

243 u

Category

actinide

Phase

solid

Density

12 g/cm³

Electron Shells

2, 8, 18, 32, 25, 8, 2

Atomic Structure

Protons: 95 • Electrons: 95 • Neutrons: Varies by isotope

Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f⁷

Discovery

1944 • Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, Albert Ghiorso