Answer:
Ionic bonding is the type of bond that is made between a nonmetal and a metal. In this type of union, one of the elements yields electrons and the other accepts electrons.
In this case, the metal is Lithium, we need a nonmetal to complete the union. (Don't know if you need this or anything but here you go)
Beryllium is a metal.
Calcium is a metal.
Fluoride is a nonmetal.
Sodium is a metal.
After the analysis, we conclude that the correct answer is Fluoride since it is the only one that is a nonmetal.
