Fm Fermium
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

Fermium is a synthetic element with symbol Fm and atomic number 100. It is a member of the Actinide series. It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared.
It belongs to group of the periodic table having trivial name .
Fermium Facts
Read key information and facts about element Fermium
Name | Fermium |
Atomic Number | 100 |
Atomic Symbol | Fm |
Atomic Weight | 257 |
Phase | Solid |
Color | - |
Appearance | - |
Classification | Actinide |
Group in Periodic Table | - |
Group Name | |
Period in Periodic Table | period 7 |
Block in Periodic Table | f -block |
Electronic Configuration | [Rn] 5f12 7s2 |
Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 32, 30, 8, 2 |
Melting Point | 1800 K |
Boiling Point | - |
CAS Number | CAS7440-72-4 |
How to Locate Fermium on Periodic Table
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 100 to find Fermium on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Fermium on periodic table look for cross section of group - and period 7 in the modern periodic table.
Fermium History
The element Fermium was discovered by A. Ghiorso et al.(Argonne Laboratory, Los Alamos Laboratory and University of California, Berkeley) in year 1952 in United States. Fermium was first isolated by in . Fermium derived its name from Enrico Fermi, physicist.
Formed in the first thermonuclear explosion in November 1952, by irradiation of uranium with neutrons; kept secret for several years.
Fermium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Fermium in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
ppb by weight (1ppb =10^-7 %) | ppb by atoms (1ppb =10^-7 %) | |
---|---|---|
Abundance in Universe | - | - |
Abundance in Sun | - | - |
Abundance in Meteorites | - | - |
Abundance in Earth's Crust | - | - |
Abundance in Oceans | - | - |
Abundance in Humans | - | - |
Crystal Structure of Fermium
The solid state structure of Fermium is Body Centered Cubic.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
Unit Cell Parameters
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
a | b | c |
---|---|---|
and the angles between them Lattice Angles (alpha, beta and gamma).
alpha | beta | gamma |
---|---|---|
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
Space Group Name | - |
Space Group Number | - |
Crystal Structure | Body Centered Cubic |
Number of atoms per unit cell | 2 |

The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Fermium Atomic and Orbital Properties
Fermium atoms have 100 electrons and the electronic shell structure is [2, 8, 18, 32, 30, 8, 2] with Atomic Term Symbol (Quantum Numbers) 3H6.
Atomic Number | 100 |
Number of Electrons (with no charge) | 100 |
Number of Protons | 100 |
Mass Number | 257 |
Number of Neutrons | 157 |
Shell structure (Electrons per energy level) | 2, 8, 18, 32, 30, 8, 2 |
Electron Configuration | [Rn] 5f12 7s2 |
Valence Electrons | 5f12 7s2 |
Valence (Valency) | 3 |
Main Oxidation States | 3 |
Oxidation States | 2, 3 |
Atomic Term Symbol (Quantum Numbers) | 3H6 |
Bohr Atomic Model of Fermium - Electrons per energy level

n | s | p | d | f |
---|
Ground State Electronic Configuration of Fermium - neutral Fermium atom
Abbreviated electronic configuration of Fermium
The ground state abbreviated electronic configuration of Neutral Fermium atom is [Rn] 5f12 7s2. The portion of Fermium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Rn]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 5f12 7s2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Fermium
Complete ground state electronic configuration for the Fermium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f12 7s2
Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.

Atomic Structure of Fermium
Fermium atomic radius is - , while it's covalent radius is - .
Atomic Radius Calculated | - (0 Å) |
Atomic Radius Empirical | - (0 Å) |
Atomic Volume | - |
Covalent Radius | - |
Van der Waals Radius | - |
Neutron Cross Section | 5800 |
Neutron Mass Absorption | - |
Atomic Spectrum of Fermium
Fermium Chemical Properties: Fermium Ionization Energies and electron affinity
The electron affinity of Fermium is - .
Valence | 3 |
Electronegativity | 1.3 |
ElectronAffinity | - |
Ionization Energy of Fermium
Refer to table below for Ionization energies of Fermium
Ionization energy number | Enthalpy - kJ/mol |
---|---|
1st | 627 |
Fermium Physical Properties
Refer to below table for Fermium Physical Properties
Density | - |
Molar Volume | - |
Elastic Properties
Young Modulus | - |
Shear Modulus | - |
Bulk Modulus | - |
Poisson Ratio | - |
Hardness of Fermium - Tests to Measure of Hardness of Element
Mohs Hardness | - |
Vickers Hardness | - |
Brinell Hardness | - |
Fermium Electrical Properties
Fermium is Conductor of electricity. Refer to table below for the Electrical properties ofFermium
Electrical Conductivity | - |
Resistivity | - |
Superconducting Point | - |
Fermium Heat and Conduction Properties
Thermal Conductivity | - |
Thermal Expansion | - |
Fermium Magnetic Properties
Magnetic Type | - |
Curie Point | - |
Mass Magnetic Susceptibility | - |
Molar Magnetic Susceptibility | - |
Volume Magnetic Susceptibility | - |
Optical Properties of Fermium
Refractive Index | - |
Acoustic Properties of Fermium
Speed of Sound | - |
Fermium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Fermium
Melting Point | 1800 K (1526.85°C, 2780.33 °F) |
Boiling Point | - (-273.15°C, -459.66999999999996 °F) |
Critical Temperature | - |
Superconducting Point | - |
Enthalpies of Fermium
Heat of Fusion | - |
Heat of Vaporization | - |
Heat of Combustion | - |
Fermium Isotopes - Nuclear Properties of Fermium
Fermium has 19 isotopes, with between 242 and 260 nucleons. Fermium has 0 stable naturally occuring isotopes.
Isotopes of Fermium - Naturally occurring stable Isotopes: -.
Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
---|---|---|---|---|---|---|
242Fm | 100 | 142 | 242 | Synthetic | ||
243Fm | 100 | 143 | 243 | Synthetic | ||
244Fm | 100 | 144 | 244 | Synthetic | ||
245Fm | 100 | 145 | 245 | Synthetic | ||
246Fm | 100 | 146 | 246 | Synthetic | ||
247Fm | 100 | 147 | 247 | Synthetic | ||
248Fm | 100 | 148 | 248 | Synthetic | ||
249Fm | 100 | 149 | 249 | Synthetic | ||
250Fm | 100 | 150 | 250 | Synthetic | ||
251Fm | 100 | 151 | 251 | Synthetic | ||
252Fm | 100 | 152 | 252 | Synthetic | ||
253Fm | 100 | 153 | 253 | Synthetic | ||
254Fm | 100 | 154 | 254 | Synthetic | ||
255Fm | 100 | 155 | 255 | Synthetic | ||
256Fm | 100 | 156 | 256 | Synthetic | ||
257Fm | 100 | 157 | 257 | Synthetic | 100.5 d | AlphaEmission |
258Fm | 100 | 158 | 258 | Synthetic | ||
259Fm | 100 | 159 | 259 | Synthetic | ||
260Fm | 100 | 160 | 260 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
Database Search
List of unique identifiers to search the element in various chemical registry databases
Database | Identifier number |
---|---|
CAS Number - Chemical Abstracts Service (CAS) | CAS7440-72-4 |
RTECS Number | - |
CID Number | - |
Gmelin Number | - |
NSC Number | - |
Compare Fermium with other elements
Compare Fermium with all Group elements
Compare Fermium with all Period 7 elements
Compare Fermium with all Actinide elements
FAQs
What is the electronic configuration of Fermium?
The electronic configuration of Fermium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f12 7s2.
What is the abbreviated electronic configuration of Fermium?
The abbreviated electronic configuration of Fermium is [Rn] 5f12 7s2. To form abbreviated notation of electronic configuration, the completely filled subshells are replaced by the noble gas of the preceding period in square brackets.
What is the symbol of Fermium?
Symbol of Fermium is Fm. Fermium is a chemical element with symbol Fm and atomic number 100.
What is the position of Fermium in the Periodic Table?
Fermium is a chemical element with the symbol Fm and atomic number 100. Fermium is the 100 element on the periodic table. It is located in group null and period 7 in the modern periodic table.
What is the atomic number of Fermium?
The atomic number of Fermium is 100.
What is the color of Fermium?
Fermium is of color.
Who discovered Fermium?
The element Fermium was discovered by A. Ghiorso et al.(Argonne Laboratory, Los Alamos Laboratory and University of California, Berkeley) in year 1952 in United States. Fermium was first isolated by undefined in undefined.
How many valence electrons does a Fermium atom have?
Fermium has 3 valence electrons. Fermium has 100 electrons out of which 3 valence electrons are present in the 5f12 7s2 outer orbitals of atom.
What is the melting Point of Fermium?
Melting Point of Fermium is 1800 K.
What is the boiling Point of Fermium?
Boiling Point of Fermium is null K.
What is the melting Point of Fermium in Kelvin?
Melting Point of Fermium in Kelvin is 1800 K.
What is the boiling Point of Fermium in Kelvin?
Boiling Point of Fermium in Kelvin is null K.
What is the electronic configuration of Fermium 100?
The electronic configuration of Fermium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f12 7s2.
How do you write the electron configuration for Fermium?
The electronic configuration of Fermium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f12 7s2.