00:03
Hi there.
00:04
In this question, we have an aluminum ion that seems to have a single negative charge.
00:12
All right.
00:12
Well, as we look at the periodic table, aluminum is atomic number 13.
00:17
So a neutral atom of aluminum, one that doesn't have a charge, a neutral atom would have 13 protons.
00:32
And because it has 13 protons, it would have to have 13 electrons.
00:38
Well, when we form an ion with a negative charge, that means it has gained one electron.
00:52
So therefore, if the neutral atom has 13 electrons, and this has gained one electron, it now would have 14 electrons.
01:05
So we need to write an electron configuration for 14 electrons.
01:10
Well, to do that, we would start with the noble gas in the previous period.
01:17
Which is neon.
01:19
That represents the first 10 electrons, the core electrons...