• Name: Protactinium

  • Symbol: Pa

  • Number of Energy Levels: 7

  • Electrons on the outer energy level: 2

  • Atomic Number: 91

  • Atomic Mass: 231.03 Amu

  • Protons / Electrons: 91

  • Neutrons: 140

  • Density: 15.4 g/cm3

  • Classification: Rare Earth

Top 11 interesting facts about Protactinium

  • Protactinium was discovered in 1917 by Otto Hahn and Lise Meitner. Its name derives from the Greek word "protos" which means "first".
  • Protactinium's melting point is at 1600.0 C (1873.15 K, 2912.0 F) and its boiling point is believed to be at 4027 C.
  • Protactinium is a dense chemical element.
  • Protactinium has a silvery-gray color.
  • Protactinium reacts with oxygen and water.
  • Protactinium is denser than thorium but lighter than uranium.
  • Protactinium is used just for research purposes.
  • Protactinium is found in Earth's crust mostly in some uranite ores.
  • Protactinium is mostly produced from spent nuclear fuel as an intermediate product of nuclear fission in thorium reactors.
  • Protactinium has 29 radioisotopes (all unstable but the most stable isotope is 231-Protactinium).
  • Protactinium is highly radioactive and very toxic.