19

K

Potassium
39.0983 (1)
 Historical Information

Until the 18th century no distinction was made between potassium and sodium. Well before potassium was recognized as an element, potassium carbonate was mixed with animal fat to make soap. The carbonate was made by extracting wood ash with water before concentration by boiling - hence the name "potash" for potassium salts.
Basic Information Shells
  • Name:Potassium
  • Symbol: K
  • Atomic number: 19
  • Atomic weight:39.0983 (1)
  • Standard state: solid at 298 K
  • Group in periodic table: 1
  • Group name:Alkali metal
  • Period in periodic table: 4
  • Block in periodic table: s-block
  • Classification: Metallic
 potassium
Uses Trivia
  • the alloy of potassium with sodium (NaK) is used as a heat-transfer medium in nuclear reactors. The alloy is liquid at ambient temperature and is a good reducing agent in the chemistry laboratory

It is obtained by electrolysis of the chloride or hydroxide, much in the same manner as prepared by Davy. It is one of the most reactive and electropositive of metals and, apart from lithium, it is the least dense known metal.