Britannica Sources used in this answer

How many electrons are in the outer shell of a potassium atom?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A periodic table element box for potassium shows atomic number 19, symbol K, atomic weight 39.0983, electron configuration [Ar]4s1, and name potassium. Icons indicate it is an alkali metal, solid at room temperature, body-centered cubic crystal structure, and has strongly basic higher-valence oxides. A key explains the symbols for alkali metals, solid state, body-centered cubic structure, and strong basicity. — potassium Properties of potassium.

A potassium atom has one electron in its outer shell.

This is represented by the electron configuration $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1}$ , or more simply as 2-8-8-1. The single electron in the 4s orbital is easily lost, which is why potassium typically exhibits an oxidation state of +1 in its chemical compounds.12