A Visual Encyclopedia of the Periodic Table

30

Alkali Metals

Laboratory sample

of pure potassium

in an airless vial

Potash

Forms

Potassium

19

K

Soft and

shiny solid

This mineral

is rich in

potassium chloride.

This mineral contains

potassium chloride, which

gives it a salty taste.

19 19 20

State: Solid

Discovery: 1807

This glass case holding pure

potassium has no air in it,

preventing the metal from

reacting with oxygen in air.

Potassium was first found in the dust of

burnt plants. It was discovered by Sir Humphry

Davy when he experimented with potash –

a mixture of substances made from the ash

of burnt plants soaked in water. The name

potassium comes from potash but the

element’s chemical symbol, K, is taken from

kalium, a Latin word for “ash”. Potassium is never

found pure in nature, but is present in minerals

such as aphthitalite and sylvite. Potassium is

vital for the human body, helping muscles and

nerves work properly. For this, we rely on

Sy

lvit

e

The yellow and

green colour comes

from impurities.

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