Discovery date : 1807
Discovered by: Humphry Davy
Origin of the name: The name is derived from the English word 'potash'.
Allotropes :
~>POTASSIUM is a chemical element with symbol K and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals.
FACT BOX | |||
Group | 1 | Melting point | 63.5°C, 146.3°F, 336.7 K |
Period | 4 | Boiling point | 759°C, 1398°F, 1032 K |
Block | s | Density (g cm−3) | 0.89 |
Atomic number | 19 | Relative atomic mass | 39.098 |
State at 20°C | Solid | Key isotopes | 39 K |
Electron configuration | [Ar] 4s1 | CAS number | 7440-09-7 |
ChemSpider ID | 4575326 | ChemSpider is a free chemical structure database |
Potassium salts in the form of saltpetre (potassium nitrate, KNO3), alum (potassium aluminium sulfate, KAl(SO4)2), and potash (potassium carbonate, K2CO3) have been known for centuries. They were used in gunpowder, dyeing, and soap making. They were scraped from the walls of latrines, manufactured from clay and sulfuric acid, and collected as wood ash respectively. Reducing them to the element defeated the early chemists and potassium was classed as an ‘earth’ by Antoine Lavoisier. Then in 1807, Humphry Davy exposed moist potash to an electric current and observed the formation of metallic globules of a new metal, potassium. He noted that when they were dropped into water they skimmed around on the surface, burning with a lavender-coloured flame.