PROTOACTINIUM

The protactinio is a chemical element of the periodic table which symbol is Pa. His atomic number is 91.
It has high radioactivity and toxicity, nowadays uses do not exist for the protactinio out of the scientific basic investigation.
The protactinio is a metallic silver element that belongs to the group of the actínidos, which presents a metallic intense sheen.
The protactinio (of protos, first and actinium) was identified by the first time in 1913 when Kasimir Fajans and O.H. Göhring found the isotope of short life Pa.
The name changed to Protoactinium in 1918 when two groups of scientists (Otto Hahn and Lise Meitner of Germany, and Frederick Soddy and John Cranston of the United Kingdom) discovered it in an independent way, and they shortened the name to protactinium (in Spanish, protoactinio) in 1949.

Information obtained of www.wikipedia.org and www.lenntech.es