Argon
---
| General Properties | |
|---|---|
| Atomic number | 18 |
| Atomic mass | 39.95amu |
| Atomic radius | 71pm |
| Electron Configuration | [Ne] 3s2 3p6 |
| Density | 0.00163g/cm3 |
| Melting point | -189.3°C |
| Boiling point | -185.8°C |
| First discovered/ developed | 1894 |
---
Description and uses
Argon is the 18th element in the periodic table. It was discovered in 1894 by William Ramsay, when he extracted it from liquid air. He noticed that around 1% of
it would not react, which is a common property of noble gases. It is the third most abundant gas in the atmosphere.
Argon is commonly used as an inert atmosphere, such as during galvanisation, as if the metal was heated to the necessary temperatures in air, it would quickly
react with the oxygen, and form a useless dust. Other examples of this use include the production of
titanium and welding.
Argon has 4 naturally occurring isotopes, with atomic weight ranging from 36 to 40. The most abundant isotope of argon is 40Ar, taking up around
99.6% of all argon atoms. It is formed in our atmosphere by the radioactive decay of 40K. The least abundant isotope of argon is the radioactive
40Ar with a half-life of around 268 years.