Question #e25d5

Potassium chloride, #"KCl"#, is an ionic compound formed by the electrostatic force of attraction that holds the potassium cations and the chlorine anions together.

Potassium, #"K"#, is located in group 1 of the Periodic Table. This tells you that a potassium atom has #1# electron in its outermost shell, i.e. #1# valence electron.

In order to complete its octet, a potassium atom must lose that valence electron. When that happens, the potassium cation, #"K"^(+)#, is formed.

Chlorine, #"Cl"#, is located in group 17 of the Periodic Table. This tells you that a chlorine atom has #7# electrons in its outermost shell.

In order to complete its octet, a chlorine atom must gain #1# valence electron. When that happens, the chloride anion, #"Cl"^(-)#, is formed.

Now, when potassium reacts with chlorine, the former loses its valence electron and the latter takes it. The two resulting ions, i.e. the potassium cation and the chloride anion, are then bonded together by the electrostatic force of attraction #-># an ionic bond is formed.

You can thus say that you have

#["K"^(+)] * ["Cl"^(-)] -> ["K"^(+)]["Cl"^(-)]#

The balanced chemical equation that describes this reaction looks like this

#2"K"_ ((s)) + "Cl"_ (2(g)) -> 2"KCl"_ ((s))#