Fermium

Fermium (Fm)

chemical element with the atomic number of 100
Atomic Number100
Atomic Weight257
mass number241
Group
Period7
Blockf
proton100 p+
neutron141 n0
electron100 e-
Animated Bohr model of Fm (Fermium)

Āhuatanga Ōkiko

Atomic Radius
molar volume
covalent radius
167 pm
Metallic Radius
ionic radius
110.5 pm
Crystal Radius
124.5 pm
Van der Waals radius
245 pm
density
9.7 g/cm³

Chemical Property

energy
proton affinity
electron affinity
ionization energy
ionization energy of Fm (Fermium)
enthalpy of vaporization
enthalpy of fusion
standard enthalpy of formation
electron
electron shell2, 8, 18, 32, 30, 8, 2
Bohr model: Fm (Fermium)
valence electron2
Lewis structure: Fm (Fermium)
electron configuration[Rn] 5f12 7s2
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 5f12 7s2
Enhanced Bohr model of Fm (Fermium)
Orbital Diagram of Fm (Fermium)
oxidation number2, 3
electronegativity
Electrophilicity Index
fundamental state of matter
phase of matterSolid
gaseous state of matter
Boiling Point
Melting Point
1,800.15 K
critical pressure
critical temperature
triple point
appearance
color
Colorless
appearance
refractive index
thermodynamic material property
Thermal Conductivity
thermal expansion
molar heat capacity
Specific Heat Capacity
heat capacity ratio
electrical properties
type
electrical conductivity
electrical resistivity
superconductivity
magnetism
type
magnetic susceptibility (Mass)
magnetic susceptibility (Molar)
magnetic susceptibility (Volume)
magnetic ordering
Curie temperature
Néel temperature
structure
Crystal Structure ()
lattice constant
Lattice Angles
mechanical property
hardness
bulk modulus
shear modulus
Young's modulus
Poisson's ratio
speed of sound
classification
CategoryActinides, Actinides
CAS Group
IUPAC Group
Glawe Number44
Mendeleev Number36
Pettifor Number37
Geochemical Class
Goldschmidt classificationsynthetic

other

Gas Basicity
polarizability
113 ± 20 a₀
C6 Dispersion Coefficient
allotrope
Neutron cross section
5,800
Neutron Mass Absorption
quantum number3H6
space group ()

Isotopes of Fermium

Stable Isotopes0
Unstable Isotopes20
Natural Isotopes0

241Fm

mass number241
neutron number141
relative atomic mass
241.074311 ± 0.000322 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
730 ± 60 us
spin5/2
nuclear quadrupole moment
time of discovery or invention2008
parity+

decay modeintensity
SF (spontaneous fission)
α (α emission)14%
β+ (β+ decay; β+ = ϵ + e+)12%

242Fm

mass number242
neutron number142
relative atomic mass
242.07343 ± 0.00043 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
800 ± 200 us
spin0
nuclear quadrupole moment
0
time of discovery or invention1975
parity+

decay modeintensity
SF (spontaneous fission)100%
α (α emission)

243Fm

mass number243
neutron number143
relative atomic mass
243.074414 ± 0.00014 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
231 ± 9 ms
spin7/2
nuclear quadrupole moment
time of discovery or invention1981
parity-

decay modeintensity
α (α emission)91%
SF (spontaneous fission)9%
β+ (β+ decay; β+ = ϵ + e+)

244Fm

mass number244
neutron number144
relative atomic mass
244.074036 ± 0.000216 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
3.12 ± 0.08 ms
spin0
nuclear quadrupole moment
0
time of discovery or invention1967
parity+

decay modeintensity
SF (spontaneous fission)97%
β+ (β+ decay; β+ = ϵ + e+)2%
α (α emission)1%

245Fm

mass number245
neutron number145
relative atomic mass
245.075354 ± 0.00021 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
4.2 ± 1.3 s
spin1/2
nuclear quadrupole moment
0
time of discovery or invention1967
parity+

decay modeintensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)7%
SF (spontaneous fission)0.3%

246Fm

mass number246
neutron number146
relative atomic mass
246.075353334 ± 0.000014675 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
1.54 ± 0.04 s
spin0
nuclear quadrupole moment
0
time of discovery or invention1966
parity+

decay modeintensity
α (α emission)93.2%
SF (spontaneous fission)6.8%
ϵ (electron capture)1.3%

247Fm

mass number247
neutron number147
relative atomic mass
247.076944 ± 0.000194 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
31 ± 1 s
spin7/2
nuclear quadrupole moment
time of discovery or invention1967
parity+

decay modeintensity
α (α emission)64%
β+ (β+ decay; β+ = ϵ + e+)

248Fm

mass number248
neutron number148
relative atomic mass
248.077185451 ± 0.000009122 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
34.5 ± 1.2 s
spin0
nuclear quadrupole moment
0
time of discovery or invention1958
parity+

decay modeintensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)
SF (spontaneous fission)0.1%

249Fm

mass number249
neutron number149
relative atomic mass
249.078926042 ± 0.000006668 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
1.6 ± 0.1 m
spin7/2
nuclear quadrupole moment
time of discovery or invention1960
parity+

decay modeintensity
β+ (β+ decay; β+ = ϵ + e+)
α (α emission)33%

250Fm

mass number250
neutron number150
relative atomic mass
250.079519765 ± 0.000008468 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
31 ± 1.1 m
spin0
nuclear quadrupole moment
0
time of discovery or invention1954
parity+

decay modeintensity
α (α emission)100%
SF (spontaneous fission)0.0069%
ϵ (electron capture)

251Fm

mass number251
neutron number151
relative atomic mass
251.08154513 ± 0.000015342 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
5.3 ± 0.08 h
spin9/2
nuclear quadrupole moment
time of discovery or invention1957
parity-

decay modeintensity
β+ (β+ decay; β+ = ϵ + e+)98.2%
α (α emission)1.8%

252Fm

mass number252
neutron number152
relative atomic mass
252.082466019 ± 0.000005604 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
25.39 ± 0.04 h
spin0
nuclear quadrupole moment
0
time of discovery or invention1956
parity+

decay modeintensity
α (α emission)100%
SF (spontaneous fission)0.0023%
+ (double β+ decay)

253Fm

mass number253
neutron number153
relative atomic mass
253.085180945 ± 0.000001662 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
3 ± 0.12 d
spin1/2
nuclear quadrupole moment
0
time of discovery or invention1957
parity+

decay modeintensity
ϵ (electron capture)88%
α (α emission)12%

254Fm

mass number254
neutron number154
relative atomic mass
254.086852424 ± 0.000001978 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
3.24 ± 0.002 h
spin0
nuclear quadrupole moment
0
time of discovery or invention1954
parity+

decay modeintensity
α (α emission)99.9408%
SF (spontaneous fission)0.0592%

255Fm

mass number255
neutron number155
relative atomic mass
255.089963495 ± 0.000004223 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
20.07 ± 0.07 h
spin7/2
nuclear quadrupole moment
time of discovery or invention1954
parity+

decay modeintensity
α (α emission)100%
SF (spontaneous fission)2.4%

256Fm

mass number256
neutron number156
relative atomic mass
256.091771699 ± 0.000003241 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
157.1 ± 1.3 m
spin0
nuclear quadrupole moment
0
time of discovery or invention1955
parity+

decay modeintensity
SF (spontaneous fission)91.9%
α (α emission)8.1%

257Fm

mass number257
neutron number157
relative atomic mass
257.095105419 ± 0.000004669 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
100.5 ± 0.2 d
spin9/2
nuclear quadrupole moment
time of discovery or invention1964
parity+

decay modeintensity
α (α emission)99.79%
SF (spontaneous fission)0.21%

258Fm

mass number258
neutron number158
relative atomic mass
258.097077 ± 0.000215 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
370 ± 14 us
spin0
nuclear quadrupole moment
0
time of discovery or invention1971
parity+

decay modeintensity
SF (spontaneous fission)100%
α (α emission)

259Fm

mass number259
neutron number159
relative atomic mass
259.100596 ± 0.000304 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
1.5 ± 0.2 s
spin
nuclear quadrupole moment
time of discovery or invention1980
parity

decay modeintensity
SF (spontaneous fission)100%

260Fm

mass number260
neutron number160
relative atomic mass
260.102809 ± 0.000467 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
spin0
nuclear quadrupole moment
0
time of discovery or invention
parity+

decay modeintensity
SF (spontaneous fission)
Fermium-Ytterbium Alloy
Electron shell 100 Fermium

kōrero nehe

discoverer or inventorArgonne, Los Alamos, U of Calif
location of discoveryUnited States
time of discovery or invention1953
etymologyNamed in honor of the scientist Enrico Fermi.
pronunciationFER-mi-em (Ingarihi)

source

Abundance
Abundance in Earth's crust
natural abundance (Moana nui)
natural abundance (human body)
0 %
natural abundance (meteoroid)
0 %
natural abundance (Te Rā)
0 %
Abundance in Universe
0 %

Nuclear Screening Constants