| Content-Type | image/png |
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| Content-Length | 2.15 kB |
| Size | 512x512 |
#87 Francium - rarity ZERO-KELVIN
| 1st ionization energy | 3.9 eV | 0.85% |
|---|---|---|
| atomic mass | 223 u | 0.85% |
| atomic number | 87 | 0.85% |
| atomic radius | 348 picometers (van der Waals radius) | 0.85% |
| boiling point | 950 K or 677 °C or 1251 °F | 0.85% |
| cas number | 7440-73-5 | 0.85% |
| category | Alkali metals | 5.08% |
| crystal structure | BCC (body centered cubic) | 5.93% |
| density | 2.48 g/cm3 | 0.85% |
| electronegativity | 0.7 (Pauling scale) | 0.85% |
| electronic configuration | [Rn] 7s1 | 0.85% |
| electrons | 87 | 0.85% |
| electrons arrangement | 2, 8, 18, 32, 18, 8, 1 | 0.85% |
| main isotopes | 123Fr | 0.85% |
| melting point | 300 K or 27 °C or 81 °F | 0.85% |
| neutrons | 136 | 1.69% |
| position | Group: 1, Period: 7, Block: s | 0.85% |
| rarity | ZERO-KELVIN | 33.33% |
| state | Solid | 72.88% |
| symbol | Fr | 0.85% |
| valence electrons | 1 | 5.93% |
| who discovered | Marguerite Perey (in 1939) | 0.85% |
Total Rarity Score: 2004.75
Rarity: #43/354