When naming a compound containing potassium and chlorine, you change the suffix of the anion's name to "-ide".

Here's why:

* Potassium is a metal and forms a cation (K+).

* Chlorine is a nonmetal and forms an anion (Cl-).

* When naming ionic compounds, the metal cation is named first, followed by the nonmetal anion with its suffix changed to "-ide".

Therefore, the compound containing potassium and chlorine is called potassium chloride.