00:01
For this question, we see the trend in first ionization energy of the elements in period two going from lithium to neon.
00:11
And it looks something like this, where we've got lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon.
00:30
So there's a general increase in first ionization energy because as we go across, cross a period, what is happening is we are adding protons to the nucleus and in addition, adding electrons to the same energy level.
00:57
In this case, we're adding them to energy level 2.
01:01
If we're adding them to the same energy level, then they are about the same distance from the nucleus if we didn't take into account the increase in charge of the nucleus.
01:14
So what is happening is the effective nuclear charge is increasing.
01:26
As the effective nuclear charge increases, then those peripheral electrons, the ones that are added in last, see more of the positive charge of the nucleus and are held more tightly to the nucleus.
01:43
Thus, as the effective nuclear charge increases, it's going to be harder to remove these electrons.
01:50
And we see a general increase in the first ionization energy...