An atom of potassium (K) has one valence electron.
Potassium belongs to Group 1 (alkali metals) of the periodic table, and elements in Group 1 have one valence electron. Valence electrons are the electrons present in the outermost energy level (also known as the valence shell) of an atom. In the case of potassium, its electron configuration is [Ar] 4s1, which means it has one electron in its outermost 4s orbital. Therefore, potassium has one valence electron.