34Se78.971
Selenium
Reactive non-metalsPoor conductors that build the molecules of living things and much of the air.
[Ar] 3d¹⁰ 4s² 4p⁴
- Atomic number
- 34
- Atomic mass
- 78.971
- Protons
- 34
- Neutrons
- 45 (most common)
- Electrons
- 34
- Shells
- 2, 8, 18, 6
- State at 25 °C
- Solid
- Position
- Group 16, period 4
Proton (+)Neutron (0)Electron (−)
Discovered byJöns Jacob Berzelius, 1817Jöns Jacob Berzelius: 4 elements
Berzelius found it in sulfuric acid residue and named it after Selene, the Greek goddess of the Moon.
Did you know?
- It conducts electricity better when light shines on it.
- Your body needs a tiny amount of selenium.
Where it's found
- Copper ores, alongside sulfur
- Brazil nuts
What it's used for
- Glass making
- Solar cells
- Anti-dandruff shampoos
Try it
There's no safe home experiment for Selenium. Explore it with the animated atom above instead.