Elements · ← Th Thorium · U Uranium →
Pa Protactinium
Basic facts
| Symbol | Pa |
|---|---|
| Atomic number | 91 |
| Standard atomic weight | 231.03588 |
| Group | none (actinide series) |
| Period | 7 |
| Block | f-block |
| Category | Actinide |
| Standard state | Solid |
| Discovered | 1913 |
Source: PubChem, Protactinium (periodic table data, retrieved 2026-10-19). Group and period follow the standard 18-column periodic table.
Biotech uses & experiments
No verified biotech applications listed yet.