Fermium

Fermium (Fm)

Radioactive metallic transuranic element, belongs to the actinoids. Ten known isotopes, most stable is Fm-257 with a half-life of 10 days. First identified by Albert Ghiorso and associates in the debris of the first hydrogen-bomb explosion in 1952.
Atomic Number100
Atomic Weight257
Mass Number242
Group
Period7
Blockf
Protons100 p+
Neutrons142 n0
Electrons100 e-
Fermium-Ytterbium Alloy.jpg Electron shell 100 Fermium.svg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
Atomic Volume
Covalent Radius
167 pm
Metallic Radius
Ionic Radius
110.5 pm
Crystal Radius
124.5 pm
Van der Waals radius
245.00000000000003 pm
Density
9.7 g/cm³
Boiling Point
Melting Point
1,800 K
Electrons per shell2, 8, 18, 32, 30, 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
113 a₀
C6 Dispersion Coefficient
Oxidation States2, 3
Color
Colorless
Crystal Structure ()
Lattice Constant
Bulk Modulus
Electrical Resistivity
Electron Configuration[Rn] 5f12 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 Number44
Mendeleev Number36
Pettifor Number37
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 Fermium

Stable Isotopes
Unstable Isotopes
242Fm 243Fm 244Fm 245Fm 246Fm 247Fm 248Fm 249Fm 250Fm 251Fm 252Fm 253Fm 254Fm 255Fm 256Fm 257Fm 258Fm 259Fm 260Fm

History

Fermium was discovered as a component of the debris of the first hydrogen bomb explosion in 1952. It was identified by Albert Ghiorso and co-workers at the University of California, Berkeley in collaboration with the Argonne and Los Alamos National Laboratories, in the fallout from the Ivy Mike nuclear test. The new element was produced by the nuclear fission of 17 neutrons with uranium-238. Named after Nobel laureate Enrico Fermi, one of the pioneers of nuclear physics

DiscoverersArgonne, Los Alamos, U of Calif
Discovery LocationUnited States
Discovery Year1953
Name OriginNamed in honor of the scientist Enrico Fermi.
Fermium is harmful due to its radioactivity
Sixteen isotopes of fermium are known to exist

Uses

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

Sources

Produced by bombarding lighter transuranium elements with still lighter particles or by neutron capture.