91 Pa
Actinide
Protactinium
Rare radioactive metal.
Properties of Protactinium
- Atomic number (Z)
- 91
- Symbol
- Pa
- Atomic mass
- 231.04 g/mol
- Category
- Actinide
- Group
- 3
- Period
- 7
- Electron configuration
- [Rn] 5f² 6d¹ 7s²
- Electronegativity (Pauling)
- 1.5
- Atomic radius
- 180 pm
- First ionization energy
- 568 kJ/mol
- Melting point
- 1841 K (1567.8 °C)
- Boiling point
- 4300 K (4026.8 °C)
- Density
- 15.37 g/cm³
- Phase at 25 °C
- Solid
- Discovered
- Discovered in 1913
Frequently asked questions
What is Protactinium?
Protactinium (Pa) is an actinide, element number 91 on the periodic table. Rare radioactive metal.
What is the atomic number and atomic mass of Protactinium?
Protactinium has atomic number 91 and an atomic mass of about 231.04 g/mol.
What is the electron configuration of Protactinium?
The electron configuration of Protactinium is [Rn] 5f² 6d¹ 7s².
Where is Protactinium on the periodic table?
Protactinium sits in group 3, period 7, and is classified as a actinide.