Protactinium

Actinide

Symbol: Pa

Atomic Number: 91

Standard State: Solid

Atomic Mass: 231.0359

Electron Configuration: [Rn]7s2 5f2 6d1

Electronegativity: 1.5

Atomic Radius: 243

Ionization Energy: 5.89

Melting Point: 1845

Boiling Point:

Density: 15.37

Year Discovered: 1913