Potassium was discovered by Sir Humphrey Davy in 1807 in England. Potassium was the first metal that was isolated by electrolysis. Potassium in nature occurs only in ionic salts.
Atomic number: 19
Atomic weight: 39.098
Group, period, block: 1, 4, s
Color: silvery gray
Classification: alkali metal
Electron configuration: 4s1
Density: 0.862 g/cm-3
Melting point: 336.53 K, 63.38 °C, 146.08 °F
Boiling point: 1032 K, 759 °C, 1398 °F
Oxidation states: 1
Electronegativity: 0.82 (Pauling scale)
Ionization energies: 1st: 418.8 kJ·mol-1
Covalent radius: 203±12 pm
Van der Waals radius: 275 pm
There are three naturally occurring isotopes of potassium exist, 39K, 40K and 41K.
40K is radioactive isotope.