General

Protactinium (Pa) properties


Atomic mass, symbol and atomic number

protactinium is a natural element with the element symbol Pa and atomic number 91. In the periodic table it belongs to the actinoids with an atomic mass of 231.035 u. The chemical element discovered by Fajans and Göhring in 1913 is radioactive and is in a solid state of aggregation at room temperature.

Profile: Protactinium (English: Protactinium)

General
Chemical element:protactinium
Symbol:Pa
Atomic number:91
Group:actinides
Period:7
Block:f-block
Series:actinides
Appearance:Gray
explorers:Kasimir Fajans and Oswald Göhring
Year of discovery:1913
Atomic properties
Atomic mass:231,035 u
Atomic radius:180 pm
Covalent radius:200 pm
Van der Waals radius:
Electron configuration:Rn 7s2 5f2 6d1
ionization:568 kJ / mol
Physical Properties
Physical state:firmly
Density:15.37 g / cm3
Crystal structure:tetragonal
Magnetism:unknown
molar volume:15,18 · 10-6 m3/ mol
Mohs hardness:unknown
Melting point:1568 ° C
Boiling point:4027 ° C
Heat of fusion:15 kJ / mol
Heat of vaporization:470 kJ / mol
Thermal conductivity:47 W
Chemical properties
electronegativity:1,5

Did you know that ...

  • Protactinium due to its enormous decay rate early brevium (from lat. Brevis = short) was called?
  • Protactinium is only an intermediate in the decomposition of uranium?
  • Protactinium belongs to the rarest elements of the periodic table?