Pa
Protactinium Symbol (Pa)
Protactinium is element 91 of the periodic table. Copy its symbol Pa and see its atomic weight, electron configuration and physical properties.
What does Pa mean?
Pa is the chemical symbol for protactinium, element number 91 in the periodic table. Protactinium is an actinide in the f-block, period 7. It is a solid at room temperature and was discovered in 1913.
Codes and properties
| Chemical symbol | Pa |
|---|---|
| Atomic number (Z) | 91 |
| Atomic weight (PubChem) | 231.03588 |
| Group / period | f-block / 7 |
| Element category | actinide |
| Electron configuration | [Rn]7s² 5f² 6d¹ |
| State at 20 °C | Solid |
| Oxidation states | +5, +4 |
| Electronegativity (Pauling) | 1.5 |
| Melting point | 1845 K (1571.85 °C) |
| Density | 15.37 g/cm³ |
| Discovered | 1913 |
How to type Pa
- Plain text: type
Pa— element symbols are ordinary Latin letters, with the first letter capitalised and the second lowercase. - Subscripts in formulas: use Unicode subscript digits (₀₁₂₃₄₅₆₇₈₉) for formulas such as H₂O — copy them from the chemistry keyboard.
- LaTeX: write
\mathrm{Pa}in math mode, or use the mhchem package:\ce{Pa}. - HTML:
Pa; for subscripts use<sub>, e.g.H<sub>2</sub>O.
Frequently asked questions
What is the chemical symbol for protactinium?
The chemical symbol for protactinium is Pa.
What is the atomic number of protactinium?
Protactinium has atomic number 91, meaning each atom has 91 protons.
What is the electron configuration of protactinium?
The ground-state electron configuration of protactinium is [Rn]7s² 5f² 6d¹.
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Reference: Protactinium on PubChem (NIH)