Mini-Video on Ion Size

Chemistry

Reaction rates

Introduction to Kinetics
Reactions in Equilibrium
Mini-Video on Ion Size
Keq Intuition (mathy and not necessary to progress)
Keq derivation intuition (can skip; bit mathy)
Heterogeneous Equilibrium
Le Chatelier's Principle
Introduction to pH, pOH, and pKw

Mini-Video on Ion Size Correcting a mistake and learning a bit about ion size

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Mini-Video on Ion Size

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In the video on solubility, I draw little pictures of sodium
and chloride ions when sodium chloride dissolves or
disassociates into water.
This is sodium and this is chloride.
And my simple brain, when I looked at it, I said, OK, how
should I draw these things?
I said, well, they're in the same period, and sodium is a
Group 1 element.
It's an alkali metal, while chlorine is a halogen, so
chlorine's going to have a smaller atomic radius.
And the logic there, just to review from the atomic table
trends, is that both of their valence electrons are in the
third shell.
Sodium only has 11 protons pulling in the center.
It has 11 in the center, and it has only one electron out
there in its valence shell.
So the attraction isn't as strong as the case of
chlorine, which has 17 protons in the center.
Although it has more valence electrons-- it has 7 of them--
these protons are going to have a stronger
attraction on them.
So if you just look at the trend in the periodic table,
you'd expect the sodium neutral atom to be bigger than
the chlorine neutral atom.
Because this guy has more protons pulling everything in.
And that's how I drew the ions in that video.
I said, oh, when I disassociate in water, I'll
have a big sodium ion and a smaller chlorine
ion, which is incorrect.
Because think about-- and this was pointed out to me by one
of the viewers, and they're correct, and I should have
realized it.
What happens when you ionize these things?
This guy will lose an electron, right?
He gives the electron to this guy.
So his electron configuration is actually going to look a
lot more like neon.
He now will have no electrons in that third shell, in the
third energy state.
So now he's going to have an atomic radius that's actually
much more similar to neon here, right?
Because he's going to have filled up the second shelf.
So actually, the sodium ion, this is completely incorrect.
The sodium ion is going to have an atomic radius not that
different than neon.
Actually, it will be even a little smaller than neon
because it has the same electron configuration, but it
has one more proton.
So the sodium ion is actually going to be smaller.
Because it gets rid of the electron in that third shell,
and the chlorine cation, gained an electron, so it has
completely completed its third shell.
So here you have where the chlorine ion
is going to be bigger.
So in that solubility video, I should've actually switched
the places between the sodium and the
chlorine, at least in size-wise.
And, of course, I showed how they disassociate in water,
and this would be attracted to the oxygen end of the water,
and you have the hydrogen end and all that.
But you can watch the solubility video for that.
It doesn't change the real takeaway from the video.
But I think this is a really interesting point that it
brings up, that when you ionize these neutral atoms, it
can significantly change, especially significantly
change their relative atomic sizes.
Anyway, hopefully, you found that interesting.

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When naming a variable, it is okay to use most letters, but some are reserved, like 'e', which represents the value 2.7831...

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At 2:33, Sal says "double bonds" but should say "single bonds."

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