Einsteinium (Es)
Einsteinium is the chemical element with atomic number 99 and symbol Es. It is a actinide in period 7, with a standard atomic weight of 252 u.
Faits essentiels
- Z
- 99
- Atomic weight
- 252 u no stable isotope
- Category
- actinide
- State at 298 K
- Solid
- Occurrence
- synthetic, radioactive
- Discovered
- 1952
- CAS
- 7429-92-7
Propriétés mesurées
| Property | Value | Source |
|---|---|---|
| Electronegativity | 1.3 | National Center for Biotechnology Information (NIH) |
| Melting point | 1,133 K | National Center for Biotechnology Information (NIH) |
| Atomic radius empirical | 245 pm | National Center for Biotechnology Information (NIH) |
| Ionization energy 1st | 619.4 kJ/mol | National Center for Biotechnology Information (NIH) |
Configuration électronique
- Noble gas notation
- [Rn] 5f¹¹ 7s²
- Full notation
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹¹ 6s² 6p⁶ 7s²
- Electrons per shell
- 2, 8, 18, 32, 29, 8, 2