(c) Would you expect salts like NaCl, which have singly charged i...

Question

(c) Would you expect salts like NaCl, which have singly charged ions, to have larger or smaller lattice energies compared to salts like CaO
which are composed of doubly-charged ions?

Accepted Answer

welcome back everyone. We need to compare the lattice energy between salts like potassium bromide that have singly charged ions and salts like barium sulfide that have doubly charged ions. So what they mean is that looking at potassium bromide, we would recall that we have the ion for potassium because it's in group one A. Being A K plus one ion. Whereas BR or bromine because it's an group seven A. Will form A B. R minus one. An ion versus our barium sulfide, which we recognize. Barium located and group two A. Will form A. B. A. Two plus carryin. Whereas sulfur located in Group six A. Will form A. S. Two minus an eye on. And that is why barium sulfide is a doubly charged ion salt where potassium bromide is a singly charged ion salt. We want to recall next what affects lattice energy. So if we think of the charge of Arkady on and an eye on. If we think of our radi of the ions and if we think of the arrangement of the ions in our crystal salt lattice, these would all be considered as factors that affect the magnitude of our lattice energy. Now the main factor out of these three would be the charge of Arkady on and an ion. And that is due to the fact that the radio of our ions are not really going to vary too much. We also want to recall the fact that lattice energy can be estimated by using the following formula where we take our and sorry, that's an equal sign there. So where we can take our cat ion charge multiplied by r an ion charge, which can then be divided by the product of our Catalan period added to. And that would be the period number on the periodic table added to our an ion period number. Now because we see in this formula that lattice energy and Catalan charge times anti in charge are all in the numerator. There's a direct relationship between lattice energy and the product of our kata in charge. Or we can just say between lattice energy and our ion charges. And if there's a direct relationship we can agree that as our charges increase, our lattice energy will also increase. And that means that looking at our salt barium sulfide, we would agree that we have doubly charged ions which are greater in charge than our potassium bromide which are again only singly charged. And so we would have a larger lattice energy. And this is why we can confirm that the correct choice to complete this example is going to be Choice B, which states that the salts with the doubly charged ions will have largest larger lattice energy compared to salts with singly charged ions. So B is our final answer. I hope everything I reviewed was clear. If you have any questions please leave them down below and I'll see everyone in the next practice video

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