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.
Read key information and facts about element Americium
|Group in Periodic Table||N/A|
|Period in Periodic Table||7|
|Block in Periodic Table||f-block|
|Electronic Configuration||[Rn] 5f7 7s2|
|Melting Point||1176 °C|
|Boiling Point||2011 °C|
|Electronic Shell Structure||[2, 8, 18, 32, 25, 8, 2]|
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 N/A and period 7 in the modern periodic table.
The element Americium was discovered by Glenn T. Seaborg in year 1944 in United States . Americium derived its name from The Americas, as the element was first synthesized on the continent, by analogy with europium
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 %)|
|Abundance in Universe||N/A|
|Abundance in Sun||None|
|Abundance in Meteorites||None|
|Abundance in Earth's Crust||None|
|Abundance in Oceans||None|
|Abundance in Humans||None|
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.
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)
and the angles between them Lattice Angles (alpha, beta and 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||P63/mmc|
|Space Group Number||194|
|Crystal Structure||Simple Hexagonal|
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.
|Number of Electrons (with no charge)||95|
|Number of Protons||95|
|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|
|Atomic Term Symbol (Quantum Numbers)||8S7/2|
Shell Structure of Americium - Electrons per energy level
The ground state 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.
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
Americium atomic radius is 175 pm, while it's covalent radius is N/A.
175 pm (1.75 Å)
|Atomic Volume||17.776152158 cm3|
|Van der Waals Radius||N/A|
|Neutron Cross Section||74 σa/barns|
The electron affinity of Americium is N/A
Refer to table below for Ionization energies of Americium
|Ionization energy number||Enthalpy - kJ/mol|
Refer to below table for Americium Physical Properties
|Molar Volume||17.776152158 cm3|
Americium is N/A of electricity. Refer to table below for the Electrical properties of Americium
|Thermal Conductivity||10 W/(m K)|
|Mass Magnetic Susceptibility||5.15×10-8|
|Molar Magnetic Susceptibility||1.251×10-8|
|Volume Magnetic Susceptibility||0.000704|
|Speed of Sound||N/A|
Refer to table below for Thermal properties of Americium
|Melting Point||1449 K (1176 °C)|
|Boiling Point||2284 K (2011 °C)|
|Heat of Fusion||N/A|
|Heat of Vaporization||N/A|
|Heat of Combustion||N/A|
Isotopes of rhodium. Naturally occurring Americium has 1 stable isotope - None.
|Isotope||Isotope Mass||% Abundance||T half||Decay Mode|
|DOT Hazard Class||N/A|
|NFPA Fire Rating||N/A|
|NFPA Health Rating||N/A|
|NFPA Reactivity Rating||N/A|
List of unique identifiers to search the element in various chemical registry databases
|CAS Number - Chemical Abstracts Service (CAS)||CAS7440-35-9|
|Alkali Metals||Alkaline Earth Metals|
|Transition Metals||Post-Transition Metals|