Mendelevium (Md)

Mendelevium is a synthetic element with symbol Md and atomic number 101. A metallic radioactive transuranic element in the actinide series, it is the first element that currently cannot be produced in macroscopic quantities.

Atomic Number

101

Atomic Mass

258 u

Phase

solid

Density

10.3 g/cm³

Electron Shells

2, 8, 18, 32, 31, 8, 2

Atomic Structure

Protons: 101 • Electrons: 101 • Neutrons: Varies by isotope

Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹³

Discovery

1955 • Albert Ghiorso, Glenn T. Seaborg, Gregory R. Choppin, Bernard G. Harvey, Stanley G. Thompson