Rubidium is potassium in the periodic table. lodine is bromine in the periodic table. Therefore, the rubidium ion is than the potassium ion, and the iodine ion is than the bromide ion. The the distance between the rubidium ion and the iodide ion is the potassium ion and the bromide ion. Therefore, the energy associated with the interaction between rubidium and iodide is atomic radius means that than that between , and the lattice energy of potassium bromide is more exothermidc.

The given blanks can be filled with below, below, larger, larger, larger, larger and smaller.

Explanation:

In the periodic table, rubidium comes below the potassium, and iodine comes below bromine. Therefore, it can be said that the ion of rubidium is larger in comparison to potassium ion, and similarly the ion of iodine is larger in comparison to the ion of bromine.  

When the atomic radius is larger it signifies that the distance in between the ion of iodine and the ion of rubidium is larger in comparison to that between the ion of potassium and the ion of bromine. Thus, smaller energy is associated with the interaction between iodine and rubidium, and potassium bromide's lattice energy is more exothermic.