Am Americium
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

Americium is a radioactive transuranic chemical element with symbol Am and atomic number 95. This member of the Actinide series is located in the periodic table under the Lanthanide element europium, and thus by analogy was named after the Americas. Americium was first produced in 1944 by the group of Glenn T.Seaborg from Berkeley, California, at the metallurgical laboratory of University of Chicago.
It belongs to group of the periodic table having trivial name .
Americium Facts
Read key information and facts about element Americium
Name | Americium |
Atomic Number | 95 |
Atomic Symbol | Am |
Atomic Weight | 243 |
Phase | Solid |
Color | Silver |
Appearance | silvery white |
Classification | Actinide |
Group in Periodic Table | - |
Group Name | |
Period in Periodic Table | period 7 |
Block in Periodic Table | f -block |
Electronic Configuration | [Rn] 5f7 7s2 |
Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 32, 25, 8, 2 |
Melting Point | 1449 K |
Boiling Point | 2284 K |
CAS Number | CAS7440-35-9 |
How to Locate Americium 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 95 to find Americium 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 Americium on periodic table look for cross section of group - and period 7 in the modern periodic table.
Americium History
The element Americium was discovered by G. T. Seaborg,R. A. James,O. Morgan and A. Ghiorso in year 1944 in United States. Americium was first isolated by in . Americium derived its name from The Americas, as the element was first synthesized on the continent, by analogy with europium.
Prepared by irradiating plutonium with neutrons during theManhattan Project.
Americium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Americium 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 Americium
The solid state structure of Americium is Simple Hexagonal.
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 |
---|---|---|
346.81 pm | 346.81 pm | 1124.1 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
alpha | beta | gamma |
---|---|---|
π/2 | π/2 | 2 π/3 |
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 | P63/mmc |
Space Group Number | 194 |
Crystal Structure | Simple Hexagonal |
Number of atoms per unit cell |

The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Americium Atomic and Orbital Properties
Americium atoms have 95 electrons and the electronic shell structure is [2, 8, 18, 32, 25, 8, 2] with Atomic Term Symbol (Quantum Numbers) 8S7/2.
Atomic Number | 95 |
Number of Electrons (with no charge) | 95 |
Number of Protons | 95 |
Mass Number | 243 |
Number of Neutrons | 148 |
Shell structure (Electrons per energy level) | 2, 8, 18, 32, 25, 8, 2 |
Electron Configuration | [Rn] 5f7 7s2 |
Valence Electrons | 5f7 7s2 |
Valence (Valency) | 4 |
Main Oxidation States | 3 |
Oxidation States | 2, 3, 4, 5, 6, 7 |
Atomic Term Symbol (Quantum Numbers) | 8S7/2 |
Bohr Atomic Model of Americium - Electrons per energy level

n | s | p | d | f |
---|
Ground State Electronic Configuration of Americium - neutral Americium atom
Abbreviated electronic configuration of Americium
The ground state abbreviated electronic configuration of Neutral Americium atom is [Rn] 5f7 7s2. The portion of Americium 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 5f7 7s2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Americium
Complete ground state electronic configuration for the Americium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 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 Americium
Americium atomic radius is 175 pm, while it's covalent radius is - .
Atomic Radius Calculated | 175 pm (1.75 Å) |
Atomic Radius Empirical | 175 pm (1.75 Å) |
Atomic Volume | 17.63 cm3/mol |
Covalent Radius | - |
Van der Waals Radius | - |
Neutron Cross Section | 74 |
Neutron Mass Absorption | - |
Atomic Spectrum of Americium
Americium Chemical Properties: Americium Ionization Energies and electron affinity
The electron affinity of Americium is - .
Valence | 4 |
Electronegativity | 1.13 |
ElectronAffinity | - |
Ionization Energy of Americium
Refer to table below for Ionization energies of Americium
Ionization energy number | Enthalpy - kJ/mol |
---|---|
1st | 578 |
Americium Physical Properties
Refer to below table for Americium Physical Properties
Density | 13.67 g/cm3 |
Molar Volume | 17.63 cm3/mol |
Elastic Properties
Young Modulus | - |
Shear Modulus | - |
Bulk Modulus | - |
Poisson Ratio | - |
Hardness of Americium - Tests to Measure of Hardness of Element
Mohs Hardness | - |
Vickers Hardness | - |
Brinell Hardness | - |
Americium Electrical Properties
Americium is Conductor of electricity. Refer to table below for the Electrical properties ofAmericium
Electrical Conductivity | - |
Resistivity | - |
Superconducting Point | 0.6 |
Americium Heat and Conduction Properties
Thermal Conductivity | 10 W/(m K) |
Thermal Expansion | - |
Americium Magnetic Properties
Magnetic Type | Paramagnetic |
Curie Point | - |
Mass Magnetic Susceptibility | 5.15e-8 m3/kg |
Molar Magnetic Susceptibility | 1.251e-8 m3/mol |
Volume Magnetic Susceptibility | 0.000704 |
Optical Properties of Americium
Refractive Index | - |
Acoustic Properties of Americium
Speed of Sound | - |
Americium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Americium
Melting Point | 1449 K (1175.85°C, 2148.5299999999997 °F) |
Boiling Point | 2284 K (2010.85°C, 3651.5299999999997 °F) |
Critical Temperature | - |
Superconducting Point | 0.6 |
Enthalpies of Americium
Heat of Fusion | - |
Heat of Vaporization | - |
Heat of Combustion | - |
Americium Isotopes - Nuclear Properties of Americium
Americium has 19 isotopes, with between 231 and 249 nucleons. Americium has 0 stable naturally occuring isotopes.
Isotopes of Americium - Naturally occurring stable Isotopes: -.
Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
---|---|---|---|---|---|---|
231Am | 95 | 136 | 231 | Synthetic | ||
232Am | 95 | 137 | 232 | Synthetic | ||
233Am | 95 | 138 | 233 | Synthetic | ||
234Am | 95 | 139 | 234 | Synthetic | ||
235Am | 95 | 140 | 235 | Synthetic | ||
236Am | 95 | 141 | 236 | Synthetic | ||
237Am | 95 | 142 | 237 | Synthetic | ||
238Am | 95 | 143 | 238 | Synthetic | ||
239Am | 95 | 144 | 239 | Synthetic | ||
240Am | 95 | 145 | 240 | Synthetic | ||
241Am | 95 | 146 | 241 | Synthetic | ||
242Am | 95 | 147 | 242 | Synthetic | ||
243Am | 95 | 148 | 243 | Synthetic | 7388 years | AlphaEmission |
244Am | 95 | 149 | 244 | Synthetic | ||
245Am | 95 | 150 | 245 | Synthetic | ||
246Am | 95 | 151 | 246 | Synthetic | ||
247Am | 95 | 152 | 247 | Synthetic | ||
248Am | 95 | 153 | 248 | Synthetic | ||
249Am | 95 | 154 | 249 | 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) | CAS7440-35-9 |
RTECS Number | - |
CID Number | - |
Gmelin Number | - |
NSC Number | - |
Compare Americium with other elements
Compare Americium with all Group elements
Compare Americium with all Period 7 elements
Compare Americium with all Actinide elements
FAQs
What is the electronic configuration of Americium?
The electronic configuration of Americium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 7s2.
What is the abbreviated electronic configuration of Americium?
The abbreviated electronic configuration of Americium is [Rn] 5f7 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 Americium?
Symbol of Americium is Am. Americium is a chemical element with symbol Am and atomic number 95.
What is the position of Americium in the Periodic Table?
Americium is a chemical element with the symbol Am and atomic number 95. Americium is the 95 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 Americium?
The atomic number of Americium is 95.
What is the color of Americium?
Americium is of Silver color.
Who discovered Americium?
The element Americium was discovered by G. T. Seaborg,R. A. James,O. Morgan and A. Ghiorso in year 1944 in United States. Americium was first isolated by undefined in undefined.
How many valence electrons does a Americium atom have?
Americium has 4 valence electrons. Americium has 95 electrons out of which 4 valence electrons are present in the 5f7 7s2 outer orbitals of atom.
What is the melting Point of Americium?
Melting Point of Americium is 1449 K.
What is the boiling Point of Americium?
Boiling Point of Americium is 2284 K.
What is the melting Point of Americium in Kelvin?
Melting Point of Americium in Kelvin is 1449 K.
What is the boiling Point of Americium in Kelvin?
Boiling Point of Americium in Kelvin is 2284 K.
What is the electronic configuration of Americium 95?
The electronic configuration of Americium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 7s2.
How do you write the electron configuration for Americium?
The electronic configuration of Americium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 7s2.