Protactinium (Pa)
Protactinium
Protactinium (Pa) is an actinide in period 7. Its relative atomic mass is 231.04 and the molar mass of the atom is 231.04 g/mol.
Atomic number 91
Atomic mass 231.04
Molar mass 231.04 g/mol
Category Actinide Solid
Properties of protactinium
| Atomic number | 91 |
|---|---|
| Symbol | Pa |
| Latin name | Protactinium |
| Relative atomic mass | 231.04 |
| Molar mass | 231.04 g/mol |
| Group, period, block | —, 7, f |
| Category | Actinide |
| State at 20 °C | Solid |
| Electron configuration | [Rn] 5f² 6d¹ 7s² |
| Electronegativity (Pauling) | 1.5 |
| Atomic radius | 180 pm |
Electron configuration of protactinium
Electrons per shell
K2L8M18N32O20P9Q2
Full notation
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f² 6s² 6p⁶ 6d¹ 7s²
Noble-gas notation
91 protons · 91 electrons[Rn] 5f² 6d¹ 7s²
Formula and compounds of protactinium
Simple substancePaprotactiniumMolar mass of Pa: 231.04 g/mol
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Frequently asked questions
The relative atomic mass of protactinium is 231.04, so the molar mass of the atom is 231.04 g/mol.
Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f² 6s² 6p⁶ 6d¹ 7s². Noble-gas notation: [Rn] 5f² 6d¹ 7s².