Element 91 of Periodic table is
Protactinium with atomic number 91,
atomic weight 231.03588.
Protactinium, symbol Pa, has a
Centered Tetragonal structure and Silver color.
Protactinium is a actinide element.
Know everything about Protactinium Facts, Physical Properties, Chemical
Properties, Electronic configuration, Atomic and Crystal Structure.
Protactinium is a chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume +4 and even +2 or +3 states.
Read key information and facts about element Protactinium
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
91 to find Protactinium 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 Protactinium on periodic
table look for cross section of group N/A and period
7 in the modern periodic table.
Interactive Periodic Table to Understand
and Learn Cool Trends
The element Protactinium was discovered by William Crookes in year
1913 in Germany and United Kingdom
derived its name from the Greek protos, 'first', and actinium, which is produced through the radioactive decay of protactinium
The table below shows the abundance of Protactinium in Universe, Sun, Meteorites,
Earth's Crust, Oceans and Human Body.
The solid state structure of Protactinium is Centered Tetragonal.
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.
Protactinium atoms have 91 electrons and
the electronic shell structure is [2, 8, 18, 32, 20, 9, 2] with Atomic Term Symbol (Quantum Numbers) 4K11/2.
Shell Structure of Protactinium - Electrons per energy
The ground state electronic configuration of Neutral Protactinium atom is
[Rn] 5f2 6d1 7s2.
The portion of Protactinium 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 5f2 6d1 7s2, electrons in
the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Protactinium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f2 6d1 7s2
Protactinium atomic radius is 180 pm, while it's covalent radius is N/A.
The electron affinity of Protactinium is N/A
Refer to table below for Ionization energies of Protactinium
Refer to below table for Protactinium Physical Properties
Protactinium is Conductor of electricity. Refer to
below for the Electrical properties of Protactinium
Refer to table below for Thermal properties of Protactinium
Isotopes of rhodium. Naturally occurring Protactinium has
1 stable isotope -
List of unique identifiers to search the element in various chemical registry databases