Elements / 34
34Se78.971
Selenium
Reactive nonmetal · p-block · ring N · spoke 16
Selenium is element 34, a reactive nonmetal. It sits on ring N (period 4) on spoke 16, the chalcogens. Follow that spoke toward the center and out again to find its chemical relatives.
Properties
| Density | 4.81 g/cm³ | Terrain → |
|---|---|---|
| Melting point | 494 K · 221 °C | Terrain → |
| Boiling point | 958 K · 685 °C | Terrain → |
| Electronegativity | 2.5510th most electronegative of 100 | Terrain → |
| First ionization energy | 941 kJ/mol | Terrain → |
| Atomic weight | 78.9718 u | Terrain → |
| Crustal abundance | 0.05 ppm | Terrain → |
| Discovered | 1817 | Terrain → |
Values from open reference data; see sources. "Terrain" opens that property as a 3D landscape across the whole spiral.
Two things you might not know
- Berzelius spotted it in a red deposit left after sulfur was burned in a sulfuric acid plant.
- Named for the Greek moon goddess, to pair with an element named for Earth. Brazil nuts are its richest dietary source.
Checked against chemicool.com.
Spoke 16: Chalcogens
Ring N (period 4)
Play with Selenium
Watch it fly into its seat, or raise the whole spiral into a landscape and see where it peaks.