Discovery date : 1955
Discovered by: Albert Ghiorso and colleagues
Origin of the name: Mendelevium is named for Dmitri Mendeleev
who produced one of the first periodic tables.
Allotropes :
~>MENDELEVIUM is a synthetic element with chemical symbol Md (formerly Mv) 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 through neutron bombardment of lighter elements. It is the third-to-last actinide and the ninth transuranic element.
| FACT BOX | |||
| Group | Actinides | Melting point | 827°C, 1521°F, 1100 K |
| Period | 7 | Boiling point | Unknown |
| Block | f | Density (g cm−3) | Unknown |
| Atomic number | 101 | Relative atomic mass | [258] |
| State at 20°C | Solid | Key isotopes | 258Md,260Md |
| Electron configuration | [Rn] 5f137s2 | CAS number | 7440-11-1 |
| ChemSpider ID | 22385 | ChemSpider is a free chemical structure database | |
Seventeen atoms of mendelevium were made in 1955 by Albert Ghiorso, Bernard Harvey, Gregory Chopin, Stanley Thompson, and Glenn Seaborg. They were produced during an all-night experiment using the cyclotron at Berkeley, California. In this, a sample of einsteinium-253 was bombarded with alpha-particles (helium nuclei) and mendelevium-256 was detected. This had a half-life of around 78 minutes. Further experiments yielded several thousand atoms of mendelevium, and today it is possible to produce millions of them. The longest lived isotope is mendelevium-260 which has a half-life of 28 days.