“Element-naming:
Consider potassium,
Alkaline nature seen
Back in the day.
Saga through history:
Named after potash;
The Latin form, ‘kalium’;
Symbol is K.”
The 19 April 2025 Bluesky poem featured the last of the week’s etymologic tributes. It celebrated a theme I’ve examined before, that of an unusual element abbreviation; in this case, the element of interest was potassium.
“Element-naming: /
Consider potassium…”
As with sodium, highlighted here a while ago, this story told through this poem can become circular. It will ultimately link potassium with its non-intuitive chemical symbol, the letter K.
(Like the last few essays, the inspiration for this poem and post were derived ultimately from Isaac Asimov’s Words of Science and the History Behind Them.)
“Alkaline nature seen /
Back in the day. /
Saga through history: /
Named after potash…”
Potassium is an alkali earth metal; it is placed in Group 1A on the Periodic Table of the Elements (PTE), and its compounds exhibit alkaline (basic) behavior. The term alkali, in turn, is derived from “al qaly” in Arabic, reflecting the plants from which such substances were found (that is, the plants in question were found near the qaly (saltwort)).
Asimov notes that ashes of these plants (the “pot ash”) could be used to form an ingredient in making an effective soap. Potash is now recognized as a combination of ionic salts with potassium acting as the common cation.
“The Latin form, ‘kalium’; /
Symbol is K.”
Potassium was one of the elements identified conclusively by Humphry Davy via electrolysis in 1807. Because it was isolated ultimately from pot ash, Davy at that time named it potassium. German chemists, in experiments with and observations of the same element around the same time, deemed it kalium, based on the Latin word.
This difference persists today! The English-language version of the PTE today reflects both influences, with symbol K and name potassium. The German-language version of the PTE lists the name for potassium as kalium and denotes element 11 (sodium) as natrium (Na), clarifying the relationship between name and symbol.
Chemphasis 
