This molecule is formed between a not very electronegative metal and a very electronegative nonmetal which means it should be an ionic compound which would mean that it would have the name of potassium oxide.
look up the naming rules for ionic compounds. I would explain it here but I don't know how to explain naming the anion part of the molecule other than it ends in ide since it is a monoatomic anion which is why oxide is in the name instead of oxygen.
I hope this helps. Let me know if anything is unclear or needs more explanation.
