Elements / 91
91Pa231.04
Protactinium
Actinide · f-block · ring Q
Protactinium is element 91, an actinide. It is one of the actinides, which the spiral keeps in line on ring Q instead of exiling them to a strip below the table.
Properties
| Density | 15.4 g/cm³ | Terrain → |
|---|---|---|
| Melting point | 1,841 K · 1,568 °C | Terrain → |
| Boiling point | 4,300 K · 4,027 °C | Terrain → |
| Electronegativity | 1.50 | Terrain → |
| First ionization energy | 568 kJ/mol | Terrain → |
| Atomic weight | 231.036 u | Terrain → |
| Crustal abundance | 1.4 × 10⁻⁶ ppm | Terrain → |
| Discovered | 1913 | Terrain → |
Values from open reference data; see sources. "Terrain" opens that property as a 3D landscape across the whole spiral.
Two things you might not know
- In 1961 the UK Atomic Energy Authority spent about US$500,000 to purify 127 grams of it from 60 tonnes of waste.
- Its name means precursor of element 89, which it decays into. Lise Meitner and Otto Hahn found a key isotope in 1917/18.
Checked against en.wikipedia.org.
Actinides
- Ac Actinium
- Th Thorium
- Pa Protactinium
- U Uranium
- Np Neptunium
- Pu Plutonium
- Am Americium
- Cm Curium
- Bk Berkelium
- Cf Californium
- Es Einsteinium
- Fm Fermium
- Md Mendelevium
- No Nobelium
Ring Q (period 7)
Play with Protactinium
Watch it fly into its seat, or raise the whole spiral into a landscape and see where it peaks.