The ionic compound, BaF2, is composed of which of the following pairs of ions?

Question

? 2 Ba+ ions and 1 F2- ion
? 1 Ba2+ ion and 1 F2- ion
? 1 Ba+ ion and 2 F- ions
? 1 Ba2- ion and 2 F+ ions
? 1 Ba2+ ion and 2 F- ions

Answer 1

Barium fluoride (BaF2) is composed of one barium ion and two fluoride ions. The correct pair of ions that make up BaF2 is:

• 1 Ba²⁺ ion and 2 F⁻ ions

This reflects the fact that barium has a +2 charge (Ba²⁺), and fluoride has a -1 charge (F⁻). Thus, two fluoride ions are needed to balance the charge of one barium ion, resulting in the neutral compound BaF2.