Copper is less reactive than potassium.

Copper and potassium are both elements on the periodic table, but they exhibit significantly different levels of reactivity. Copper is classified as a transition metal, which positions it in the middle of the periodic table. Transition metals are typically characterized by their low reactivity. Specifically, copper is quite stable and does not readily react with other elements, making it a preferred choice for applications such as wiring and plumbing due to its resistance to corrosion.

In contrast, potassium is categorized as an alkali metal, located in Group 1 of the periodic table. Alkali metals are known for their high reactivity, as they easily lose their outermost electron during chemical reactions. For instance, potassium reacts vigorously with water, resulting in the production of hydrogen gas and a strongly alkaline solution.

The disparity in reactivity between copper and potassium can be attributed to their electron configurations. Copper possesses a complete outer electron shell, which contributes to its stability and reduces its tendency to participate in chemical reactions. In comparison, potassium has a single electron in its outer shell that it seeks to lose in order to achieve a more stable electron configuration. This fundamental difference makes potassium significantly more reactive than copper.

In conclusion, the varying levels of reactivity between copper and potassium stem from their respective positions on the periodic table and their electron configurations. Copper, a transition metal, exhibits low reactivity, whereas potassium, an alkali metal, demonstrates high reactivity.