Final answer:
To rank BaO, BaCl2, and CaO in order of increasing ionic attraction, consider the charge and size of the ions. BaCl2 has weaker attraction due to its +2 and -1 charges. Between BaO and CaO, which both have +2 and -2 charges, CaO has stronger attraction because it has smaller ions.
Step-by-step explanation:
To rank the ionic compounds in order of increasing attraction between their ions, we consider both the charges on the ions and their sizes because these factors influence lattice energy. Larger and less charged ions will generally have weaker attractions between each other compared to smaller and more highly charged ions.
BaO (Barium Oxide) - Contains Ba2+ and O2- ions.
BaCl2 (Barium Chloride) - Contains Ba2+ and Cl- ions.
CaO (Calcium Oxide) - Contains Ca2+ and O2- ions.
Based on the lattice energy concept, compounds with ions of higher charges tend to have stronger attractions between ions, but as ions increase in size, their attractions tend to decrease. Since CaO and BaO both have ions with a +2 and -2 charge, their attractions are stronger than that in BaCl2, which has a +2 and -1 charge. Between BaO and CaO, the Ca2+ ion is smaller than the Ba2+ ion, leading to a stronger attraction in CaO. Therefore, the correct order from lowest to highest attraction is BaCl2, BaO, CaO.