Question

Select all that follow the trends of lattice energy:

BaO > KF
1. Fluorine is more electronegative than oxygen.
2. The ions in BaO are +2 and -2; whereas in KF they are +1 and -1.
3. The atomic radii of Ba and O are smaller than those of K and F.
4. The ions in KF are +2 and -2; whereas in BaO they are +1 and -1.
5. The atomic radii of K and F are smaller than those of Ba and O.

I have already tried 1,2,5. and 1,3,4 and only 2,5 and only 3,4 none of these combos are right--i don't understand what could be wrong!

Answer 1

I consider #1 definitely true.
I consider #2 definitely true.
I consider #4 definitely false.
#3 and #5 are opposites but I have looked up both atomic radii and ionic radii and neither makes much sense to me. Ba is smaller than K (both radii) but O is larger than F (both radii). So neither statement 3 nor 5 are true (half, but only half of each are true).
So 1,2 must be right. I consider neither 3 nor 5 to be correct. Therefore, I would go with 1 and 2 as true but since atomic radii are difficult to define, if you bomb out with 1 and 2 and you've tried 1,2 and 5 (and that's wrong), then it must be 1,2, and 4. Let me know what you find.

Answer 2

Thew answer is only #2