Periodic TableAll elementsMendelevium
No. 101
Md
258 u
Element · Actinide

Mendelevium

Mendelevium (钔, symbol Md) is chemical element number 101, an Actinide in period 7 of the periodic table, with a standard atomic weight of about 258. Synthetic actinide. Named in honor of Dmitri Mendeleev, father of the periodic table.

Period 7Group —[Rn] 5f¹³ 7s²

Properties

Atomic number101
SymbolMd
Atomic mass258 u
CategoryActinide
Period7
Group
Electron configuration[Rn] 5f¹³ 7s²
Electronegativity1.3
Covalent radius
Density10.3 g/cm³
Melting point1100 K
Boiling point
DiscoveryGhiorso et al., 1955

Overview

Synthetic actinide. Named in honor of Dmitri Mendeleev, father of the periodic table. Element 101, Mendelevium (Md), is an Actinide found in period 7. As an actinide it is typically radioactive and closely tied to nuclear technology.

Its electron configuration is [Rn] 5f¹³ 7s², with 2 electrons in the outer shell, and an electronegativity of about 1.3 (Pauling). Around 25 °C it is usually a solid; it melts near 1100 K (826.9 °C), has a density around 10.3 g/cm³.

In industry and daily life it turns up in Research. On the safety side, it carries a high hazard rating. It was first described by Ghiorso et al. in 1955.

Electron shells

Md101

Electrons per shell: 2 · 8 · 18 · 32 · 31 · 8 · 2

Main uses

Hazard

HighRadioactive

Compounds containing Mendelevium

No compounds in this knowledge base contain Mendelevium yet.

Data sources

Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.