00:01
And this question it says, given that the lattice energy of an ionic solid increases with the charges of the anion and cat anion, discuss why the formula of sodium fluoride is not naf2.
00:14
So we could take a look at this born haber cycle for the formation of sodium fluoride.
00:24
So the lattice energy, which is shown here, increases with the charges of the cation and anion.
00:35
So in naf2, you can see that sodium has a charge of positive 2 rather than positive 1 as in naf.
00:43
So therefore, the lattice energy is going to go up.
00:49
So in this case, as you can see from the born heaver cycle, we have to have these values in the cycle add up.
01:01
So all the values on the left have to add up to the same magnitude as the values on the bridge.
01:11
So mathematically, everything has to balance as shown in this diagram...