سيلينيوم (Se)
سيلينيوم is the chemical element with atomic number 34 and symbol Se. It is a لافلز نشط in period 4, group 16, with a standard atomic weight of 78.971 u.
حقائق أساسية
- Z
- 34
- Atomic weight
- 78.971 u
- Category
- لافلز نشط
- State at 298 K
- Solid
- Occurrence
- primordial
- Discovered
- 1817
- CAS
- 7782-49-2
الخصائص المقيسة
| Property | Value | Source |
|---|---|---|
| Electronegativity | 2.55 | National Center for Biotechnology Information (NIH) |
| Melting point | 493.65 K | National Center for Biotechnology Information (NIH) |
| Boiling point | 958 K | National Center for Biotechnology Information (NIH) |
| Density stp | 4.809 g/cm³ | National Center for Biotechnology Information (NIH) |
| Atomic radius empirical | 190 pm | National Center for Biotechnology Information (NIH) |
| Ionization energy 1st | 940.9 kJ/mol | National Center for Biotechnology Information (NIH) |
| Electron affinity | 195 kJ/mol | National Center for Biotechnology Information (NIH) |
التوزيع الإلكتروني
- Noble gas notation
- [Ar] 3d¹⁰ 4s² 4p⁴
- Full notation
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁴
- Electrons per shell
- 2, 8, 18, 6