Pretend you are the size of an atom and you are observing a reaction between a potassium ion and a fluorine atom. Describe how an ionic bond forms as the atoms react. Tell what happens to the valence electrons in each atom and how each atom is changed by losing or gaining electrons.

Due to periodic trends potassium would lose its one valence electron to have a more stable electron configuration equivalent to that of argon, which is a noble gas with a full octet. Fluorine would gain one valence electron to get a full octet equivalent to that of neon. Since potassium lost an electron it now has a positive charge and since fluorine gained an electron it is now negative. Since both are more stable this way as a full octet they will no longer exchange electrons but the positive potassium and negative fluorine will pull towards each other strongly forming an ionic bond.