Element 61 of Periodic table is
Promethium with atomic number 61,
atomic weight 145.
Promethium, symbol Pm, has a
Simple Hexagonal structure and Silver color.
Promethium is a lanthanide element.
Know everything about Promethium Facts, Physical Properties, Chemical
Properties, Electronic configuration, Atomic and Crystal Structure.
Promethium, originally prometheum, is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive; it is one of only two such elements that are followed in the periodic table by elements with stable forms, a distinction shared with technetium. Chemically, promethium is a lanthanide, which forms salts when combined with other elements.
Read key information and facts about element Promethium
Explore our interactive periodic table
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of
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
61 to find Promethium 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 Promethium on periodic
table look for cross section of group N/A and period
6 in the modern periodic table.
Interactive Periodic Table to Understand
and Learn Cool Trends
The element Promethium was discovered by Chien Shiung Wu in year
1945 in United States
derived its name from Prometheus of Greek mythology who stole fire from the Gods and gave it to humans
The table below shows the abundance of Promethium in Universe, Sun, Meteorites,
Earth's Crust, Oceans and Human Body.
The solid state structure of Promethium is Simple Hexagonal.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in
dimensional space to form the structure.
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell
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.
Promethium atoms have 61 electrons and
the electronic shell structure is [2, 8, 18, 23, 8, 2] with Atomic Term Symbol (Quantum Numbers) 6H5/2.
Shell Structure of Promethium - Electrons per energy
The ground state electronic configuration of Neutral Promethium atom is
[Xe] 4f5 6s2.
The portion of Promethium configuration that is equivalent to the noble gas of
the preceding period, is abbreviated as [Xe]. 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 4f5 6s2, electrons in
the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Promethium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f5 6s2
Promethium atomic radius is 205 pm, while it's covalent radius is N/A.
The electron affinity of Promethium is 50 kJ/mol
Refer to table below for Ionization energies of Promethium
Refer to below table for Promethium Physical Properties
Promethium is Conductor of electricity. Refer to
below for the Electrical properties of Promethium
Refer to table below for Thermal properties of Promethium
Isotopes of rhodium. Naturally occurring Promethium has
1 stable isotope -
List of unique identifiers to search the element in various chemical registry databases