The compound formed from potassium (K) and chlorine (Cl) ions is potassium chloride (KCl). Here's why:

* Potassium (K) is a metal in Group 1 of the periodic table. It readily loses one electron to form a +1 cation (K+).

* Chlorine (Cl) is a nonmetal in Group 17 of the periodic table. It readily gains one electron to form a -1 anion (Cl-).

To form a neutral compound, one potassium cation (K+) combines with one chloride anion (Cl-). The charges balance out, resulting in the formula KCl.