34
Se
Selenium
Selenium
Selenium (Se)
Reactive Nonmetals · Solid · Period 4 · Group 16
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Element Properties
- Atomic Number
- 34
- Symbol
- Se
- Atomic Mass
- 78.97
- Category
- Reactive Nonmetals
- Standard State
- Solid
- Period
- 4
- Group
- 16
- Electronegativity
- 2.55
- Atomic Radius
- 190
- Ionization Energy
- 9.75
- Electron Affinity
- 2.02
- Oxidation States
- +6, +4, -2
- Melting Point
- 493.65 K (220.5 °C)
- Boiling Point
- 958 K (684.85 °C)
- Density
- 4.809
- Electron Configuration
- [Ar]4s2 3d10 4p4
- Year Discovered
- 1817
Frequently asked questions
What is the atomic number of Selenium?
The atomic number of Selenium is 34, which equals the number of protons in its nucleus.
What is the atomic mass of Selenium?
The atomic mass of Selenium is approximately 78.97 u (one twelfth of the mass of a carbon-12 atom).
What is the electron configuration of Selenium?
The electron configuration of Selenium is [Ar]4s2 3d10 4p4.
Where is Selenium in the periodic table?
Selenium is located in period 4, group 16.
When was Selenium discovered?
Selenium was discovered in 1817.
Related elements
Same group
8
O
Oxygen
15.999
16
S
Sulfur
32.07
52
Te
Tellurium
127.6
84
Po
Polonium
208.982
116
Lv
Livermorium
293.205