Potassium chloride (KCl) is an ionic compound, meaning it is formed by the electrostatic attraction between positively and negatively charged ions.

Here's how to determine the valence:

* Potassium (K) is in group 1 of the periodic table, making it an alkali metal. Alkali metals have a +1 charge when they form ions.

* Chlorine (Cl) is in group 17 of the periodic table, making it a halogen. Halogens have a -1 charge when they form ions.

Therefore, in potassium chloride:

* Potassium (K) has a valence of +1.

* Chlorine (Cl) has a valence of -1.