Potassium is a highly reactive metal. It belongs to the alkali metals group in the periodic table, which also includes elements like sodium and lithium. When exposed to moisture or air, potassium readily reacts, often resulting in the formation of potassium hydroxide and potassium oxide.
This reactivity is due to its single valence electron, which it readily loses to achieve a stable electron configuration. As a result, potassium can vigorously react with water, producing hydrogen gas and heat, which can sometimes ignite the hydrogen.
In contrast, nonreactive elements, like noble gases (such as helium or neon), have completely filled electron shells and do not readily engage in chemical reactions. Thus, potassium’s tendency to react means it is definitely classified as a reactive element.