Complete the sentences to explain why the lattice energy of potassium bromide is more exothermic than the lattice energy of rubidium iodide?

The lattice energy is the amount of energy released when the ions that make up a crystal lattice are brought together. Now, this energy is dependent on the charge concentration of these ions. Both potassium and rubidium form ions with a + 1 charge, while bromine and iodine form ions with - 1 charge. However, because potassium and bromine are smaller than rubidium and iodine respectively, the charge is more concentrated. Therefore, more energy is released when potassium and bromine are brought together.