Protactinium (Pa)
A fascinating actinide element.
Protactinium is element 91 on the periodic table.
Element properties
- Atomic number
- 91
- Symbol
- Pa
- Atomic mass
- 231.04 u
- Category
- Actinide
- Period
- 7
- Group
- Not assigned
- Block
- f
- State
- Solid
- Electron configuration
- [Rn] 5f2 6d1 7s2
- Electronegativity (Pauling)
- 1.5
- Density
- 15.37 g/cm³
- Melting point
- 1568 °C
- Boiling point
- 4027 °C