00:01
So this question takes a look at periodic trends and in particular the important periodic trend of electron affinity.
00:08
Electron affinity is a measure of the energy usually released when we add an electron to an atom or to an ion.
00:17
And we're going to look at comparing the electron affinities of sulfur and oxygen.
00:25
Notice they're in the same group of the periodic table.
00:27
Now, generally speaking, the trend in electron affinity says as we move left or right across any row, the process becomes more exothermic or more negative.
00:39
More energy is released as we add electrons to atoms on the right side of the periodic table, then on the left.
00:47
And in general, as we move top to bottom, the process becomes less exothermic or less energy is released in adding electron.
00:56
As we move down a group.
00:59
And so when we compare sulfur to oxygen on the periodic table here, since sulfur is below oxygen, we would expect its electron affinity to be less exothermic than oxygen.
01:13
But that's not the case.
01:15
Sulfur is actually more exothermic in terms of its electron affinity...