00:02
There, in this question, we want the pair of elements that's going to form a covalent bond that is least polar.
00:12
Well, to do that, we're going to use electronegativities.
00:16
And the smallest difference in electronegativities will be the least polar bond.
00:42
That is because electronegativity is a measure of how strongly an atom pulls shared electrons toward it in a covalent bond.
00:50
So if it is much stronger than the other element it's bonding to, it is going to pull the electrons closer to it, making that side more negative.
01:01
If they have a more similar number, a smaller difference in other words, then they're sharing more equally and the bond would be less polar.
01:12
So we just need to look at electronegativities.
01:14
First we have oxygen bonding to hydrogen.
01:18
Looking at and electronegativities, oxygen is 3 .5, hydrogen is 2 .1, for a difference of 1 .4.
01:25
That is a quite polar bond.
01:28
Next we see aluminum and nitrogen.
01:37
All right, the nitrogen is 3 .0 for its electronegativity, whereas the aluminum is 1 .5.
01:48
So the difference between 3 .0 and 1 .5 is 1 .5...