Which of the following alkali metal halides has the largest lat-tice energy? Explain. (a) (b) (c)

Video transcript

Hello everyone today. We are being given the phone problem, identify the group to chloride with the smallest lattice energy. So it's important to note what the formula is for lattice energy. And so that formula is going to be the cat ion charge times our an ion charge over the Catalan radius plus the an ion radius. Now something that we can do is we can simplify the radius by using the period number instead. So we see here in each of these problems are Canadians are all Plus two as far as their charge goes And they're an ion charge as being chloride is going to be negative one. And if you have a reference text in your chemistry textbook, the an ion radius, so the radius of the an ion Is going to be three. And so we can see that each compound really only varies with the cat ion radius. And it's an important trend to note that when you have an increase in your radius, you're also going to have a you're going to have a decrease in your lattice energy based on this formula that we constructed. And so another trend to note is that the radius, the atomic radius on the periodic table increases down a group. So as you move down each group, the periodic radius is going to increase. And so looking at the relationship of these elements being in group two, a the compound with the smallest radius. So the smallest radius in this case here is going to be berry. Um And that gives us answer choice a barium chloride as our answer. Overall, I hope that this helped until next time.