Es
Einsteinium
Element 99 · 252.083 u
Einsteinium was discovered in the debris of the first hydrogen bomb test.
Physical Properties
| Atomic Mass | 252.083 u |
| Density | 8.84 g/cm³ |
| Melting Point | 1133.0 K |
| Boiling Point | 1269.0 K |
| Appearance | Silvery metallic (predicted) |
| State at Room Temp | Solid |
Chemical Properties
| Electronegativity | 1.3 (Pauling) |
| 1st Ionization Energy | 619.0 kJ/mol |
| Electron Affinity | -28.6 kJ/mol |
| Oxidation States | +2, +3 |
Atomic Properties
| Electron Configuration | [Rn] 5f11 7s2 |
| Atomic Radius | 203.0 pm |
| Van der Waals Radius | 245.0 pm |
Discovery
| Discovered By | Albert Ghiorso and others |
| Discovery Year | 1952 |
| Location | Berkeley, California, USA |
| Named After | Named after Albert Einstein |
About Einsteinium
Einsteinium was found in fallout from the first hydrogen bomb (Ivy Mike) in 1952 but kept secret until 1955. Only tiny amounts have been produced.
Uses & Applications
Scientific research, primarily to produce heavier elements like mendelevium.
Fun Fact
Einsteinium was secretly discovered in hydrogen bomb debris in 1952 and classified for three years.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 252 | - | 471.7 days | No |
| 253 | - | 20.47 days | No |
| 254 | - | 275.7 days | No |
Electron Configuration
[Rn] 5f11 7s2