Potassium

Definitions

1. A soft, waxy, silvery reactive metal that is never found unbound in nature; an element with atomic number 19 and atomic weight of 39.0983.
   uncountable, usually
2. A single atom of this element.
   countable, usually

Equivalents

Examples

“We all need⟳ potassium, and green vegetables are a good source.”

“This reaction substitutes a potassium for a sodium.”

CEFR level