Potassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name is derived. In the Periodic table, potassium is one of seven elements in column (group) 1 (alkali metals):they all have a single valence electron in their outer electron shell, which they readily give up to create an atom with a positive charge - a cation, and combine with anions to form salts.
Three reasons Potassium stands out
1
Important for nerve function in living organisms.
2
A naturally occurring radioactive isotope of this element contributes to background radiation inside your own body.
3
Its ions are essential for regulating the rhythm of the human heartbeat.
The ion behind every heartbeat
Potassium metal cannot be left in air or water, but potassium ions are indispensable inside cells. Carefully controlled flows of those ions help nerves signal and heart muscle reset between beats. Plants also require large amounts, which is why potassium compounds are a major component of fertilizer.
Recognizing Potassium in Elementle
If Potassium is the mystery element, guesses below atomic number 19 point up and guesses above it point down. Its symbol is K: a green letter matches the same position in that symbol, while a yellow letter belongs in another position.
The family clue turns green for alkali metal guesses. Compare Sodium (Na), number 11 and Lithium (Li), number 3: they share the family clue, but their atomic numbers and symbols help you tell them apart.
Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.
The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.