Protactinium (Pa)
Protactinium is a rare, radioactive actinide. Its name means "parent of actinium" because it decays into actinium.
Properties of Protactinium
- Atomic number
- 91
- Category
- Actinide
- Atomic mass
- 231.04 u
- Electron configuration
- [Rn] 5f² 6d¹ 7s²
- Melting point
- 1841 K (1567.85 °C)
- Boiling point
- 4300 K (4026.85 °C)
- Density
- 15.37 g/cm³
- Electronegativity (Pauling)
- 1.5
- Appearance
- Bright, silvery metallic
- Discovered by
- Kasimir Fajans (1913)
Facts about Protactinium
- Protactinium means "parent of actinium" because it decays into actinium!
- Protactinium is one of the rarest and most expensive natural elements!
- Only about 1-2 parts per trillion of protactinium exist in Earth's crust!
- Protactinium is extremely toxic and radioactive — scientists handle it with great care!