Protactinium was discovered by Otto Hahn, Lise Meitner, Frederick Soddy, John Cranston at 1913 in Germany, England.
Origin of name: from the Greek word "protos" meaning "first".
Atomic Number: 91
Atomic Weight: 231.03588
Melting Point: 1845 K (1572°C or 2862°F)
Boiling Point: Unknown
Density: 15.37 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 7 Group Number: none Group Name: Actinide