Mendelevium

Mendelevium (Md)

Radioactive metallic transuranic element. Belongs to the actinoid series. Only known isotope, Md-256 has a half-life of 1.3 hours. First identified by Glenn T. Seaborg, Albert Ghiorso and associates in 1955. Alternative name Unnilunium has been proposed. Named after the 'inventor' of the periodic table, Dmitri Mendeleev.
Atomic Number101
Atomic Weight258
Mass Number245
Group
Period7
Blockf
Protons101 p+
Neutrons144 n0
Electrons101 e-
Electron shell 101 Mendelevium.svg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
Atomic Volume
Covalent Radius
173 pm
Metallic Radius
Ionic Radius
109.5 pm
Crystal Radius
123.5 pm
Van der Waals radius
246 pm
Density
10.3 g/cm³
Boiling Point
Melting Point
1,100 K
Electrons per shell2, 8, 18, 32, 31, 8, 2
Electronegativity
Electrophilicity
Proton Affinity
Electron Affinity
Ionization Potential
Heat of Vaporization
Heat of Fusion
Heat of Formation
Molar Heat Capacity
Specific Heat Capacity
Thermal Conductivity
Gas Basicity
Dipole Polarizability
109 a₀
C6 Dispersion Coefficient
Oxidation States2, 3
Color
Colorless
Crystal Structure ()
Lattice Constant
Bulk Modulus
Electrical Resistivity
Electron Configuration[Rn] 5f13 7s2
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
Poisson Ratio
Shear Modulus
Young's Modulus
Allotropes
Alternate Names
Adiabatic Index
Appearance
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Electrical
Hardness
Magnetic Susceptibility
Magnetic
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
Classification
CategoryActinides, Actinides
CAS Group
IUPAC Group
Glawe Number45
Mendeleev Number38
Pettifor Number36
Geochemical Class
Goldschmidt Classsynthetic
Radioactivity
RadioactiveYes ☢️
Decay Mode
Half-Life
Lifetime
Abundance
Abundance in Earth's crust
Abundance in Oceans
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universena

Isotopes of Mendelevium

Stable Isotopes
Unstable Isotopes
245Md 246Md 247Md 248Md 249Md 250Md 251Md 252Md 253Md 254Md 255Md 256Md 257Md 258Md 259Md 260Md 261Md 262Md

History

Mendelevium was discovered by Albert Ghiorso, Glenn T. Seaborg, Gregory R. Choppin, Bernard G. Harvey and Stanley G. Thompson in 1955 at the University of California, Berkeley. It was produced by the bombardment of einsteinium with helium. Mendelevium was identified by chemical analysis in an ion exchange experiment. Named after Dmitri Mendeleev, who created the Periodic Table

DiscoverersG.T.Seaborg, S.G.Tompson, A.Ghiorso, K.Street Jr.
Discovery LocationUnited States
Discovery Year1955
Name OriginNamed in honor of the scientist Dmitri Ivanovitch Mendeleyev, who devised the periodic table.
Mendelevium is harmful due to its radioactivity
Mendelevium was the first element to be produced one atom at a time

Uses

Mendelevium is used for scientific research purposes only. It has no significant commercial applications.

Sources

Made by bombarding einsteinium with helium ions.