Question

Which element, when combined with fluorine, will form an ionic compound? *
oxygen
bromine
potassium
nitrogen

Answer 1

Potassium, because ionic compounds are formed with a metal and non-metal, Fluorine is a non metal but only Potassium is a metal of the list provided.

Answer 2

Ionic compound is when a metal combines with a non-metal or a metalloid. Since fluorine is a non-metal, we need a metal in order to form an ionic compound. Thus potassium is the answer.
Hope this would help :))