Elements / 18
18Ar39.95
Argon
Noble gas · p-block · ring M · spoke 18
Argon is element 18, a noble gas. It sits on ring M (period 3) on spoke 18, the noble gases. Follow that spoke toward the center and out again to find its chemical relatives.
Properties
| Density | 1.78 g/L (as a gas) | Terrain → |
|---|---|---|
| Melting point | 84 K · -189 °C | Terrain → |
| Boiling point | 87 K · -186 °C | Terrain → |
| Electronegativity | Not measured | Terrain → |
| First ionization energy | 1,521 kJ/mol4th highest ionization energy of 103 | Terrain → |
| Atomic weight | 39.9481 u | Terrain → |
| Crustal abundance | 3.5 ppm | Terrain → |
| Discovered | 1894 | 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
- Henry Cavendish suspected this unreactive gas hid in air in 1785; it was finally isolated in 1894. Until 1957 its symbol was different.
- Its name is Greek for 'lazy'; the third most abundant gas in air, it fills incandescent bulbs and shields arc welds.
Checked against en.wikipedia.org.
Spoke 18: Noble gases
Ring M (period 3)
Play with Argon
Watch it fly into its seat, or raise the whole spiral into a landscape and see where it peaks.