To form an ionic compound, lithium would need to bond with an element that readily gains an electron to form a -1 anion.
Elements that typically form -1 anions are found in group 17 (halogens), such as:
* Fluorine (F)
* Chlorine (Cl)
* Bromine (Br)
* Iodine (I)
Therefore, the element most likely to bond with lithium and form an ionic compound is chlorine (Cl). This would form lithium chloride (LiCl).