Potassium is a chemical element in the Periodic Table, which is marked with the symbol K and has an atomic number of 19. Its symbol is derived from the Neo-Latin name Kalium, which was proposed for the chemical back in 1809 by a German physicist and chemist, named Ludwig Wilhelm Gilbert. The term Kalium was later ruled out and the element was renamed to Potassium.



Potassium belongs to group 1 elements in the Periodic Table, as it is an Alkali Metal element. It’s preceded by Argon and is followed by Calcium. Potassium is a soft Alkali Metal with a silvery shiny finish, which is highly reactive to water, air and other chemical elements. Since it dissolves in water, it must be stored under paraffin oil. This chemical element shares group trends with the rest of the Alkali Metals and some of its isotopes are radioactive. Nevertheless, Potassium ions play a key function in the biological role of all living cells.


Physical Characteristics of Potassium

In terms of physical characteristics this particular chemical element shares various group trends with the rest of the Alkali Metal elements in the Periodic Table. Potassium’s natural state is solid, although it is a relatively soft and brittle Alkali Metal, and it’s white-greyish in color with a silvery shine. Its shiny surface gets tarnished and turns to greyish when it’s cut and exposed to Oxygen. It has an extremely low density like all Alkali Metals. This chemical element is the second least dense Alkali Metal after the element Lithium. When Potassium is subjected to a flame test its color changes to lilac.


Chemical Properties of Potassium


Atomic Number – 19

Group – 1

Period – 4

Block – s

Electronic Configuration – 4s1

Relative Atomic Mass – 39.098 (39.0983 g/mol)

Molecular Weight – 39.098

Electronegativity – 0.82

Density (G CM-3) – 0.862 g/cm3 at room temperature, 0.828 g/cm3 in liquid state

Melting Point – 336.7 K; 63.5 °C; 146.3 °F

Boiling Point – 1032 K; 759 °C; 1398 °F

Atomic Radius – 227pm

Isotopes – 24

Electronic Shell – 2, 8, 8, 1


Discovery of Potassium

Back in 1797 a German chemist, named Martin Klaproth, discovered the so-called “potash”. He found the new chemical element through the “potash” method of placing the ashes of burnt leaves or wood inside a pot and then adding water to the ashes, heating them and evaporating the rest of the solution. He proposed the term “Kali” for the newly discovered element. The English chemist Humphry Davy was the first one to actually isolate the element through electrolysis in 1807. In 1809 Ludwig Wilhelm Gilbert proposed to rename the element to Kalium, but eventually a Swedish chemist, named Jöns Jacob Berzelius, renamed it to Potassium in 1814.


Recognized by: Martin Klaproth (1797)

Known and discovered by: Humphry Davy (1807)

Named by: Jöns Jacob Berzelius (1814)


Uses and role of Potassium

Potassium ions have a key function for the biological role of all living cells. They are of extreme importance for nerve transmissions and normal heart functions. This chemical element also has various industrial applications.


Potassium is widely used in gardening as a strong fertilizer. More than 90% of the overall production of this Periodic element is intended for hydroponic, agriculture and horticulture purposes. It also finds application as human food and is found in bananas, white beans, potatoes, tomato paste, beet greens, and orange juice. One of the most common Potassium salts is actually the main ingredient in baking soda. From the various industrial uses of Potassium the most common are the manufacturing of TV tubes, glass, pigments and dyes for textiles, fluorescent lamps. It also finds applications in metallurgy, gold mining, and magnetometers. Another important application of Potassium is in respiration systems for mine workers, astronauts, and infantrymen.


Potassium on Earth

This chemical element does not occur in its natural state on Earth because of its high reactivity to water and air. Potassium and its compounds can be found in various igneous rocks in the Earth’s crust, like in granite for example. While it can’t exist in its natural form, Potassium is actually the 8th most abundant element of the Periodic Table on our planet.



Various uses of Potassium have been discovered through the years. One of its most significant and historical discoveries, however, has changed the course of history tremendously. Potassium is the main ingredient in lethal injections, which are administered as a death penalty in the US, Vietnam, Thailand, China, and Guatemala.