Let's talk about ionic bonding in much more
depth. In the previous video we talked about the
basic fundamentals of how ionic bonds get made in sodium chloride. Now I want to look at why and how these steps
happen during the formation of ionic bonds. In order to really understand what's going
on in ionic bonding, we have to take a look at the individual electrons that live in sodium
and live in chlorine. Now as you probably know, there are specific
places in an atom where electrons can live. Ok I have a diagram of this here. If this is new, you should check out my video
called Valiance Electrons and the Periodic Table. Anyway, each one of these little circles represents
a spot that an electron can live in in an atom. And you'll see that these little electron
spots are arranged in rings around the nucleus, the atom. Each one of these rings is called a shell
or an energy level. Ok so we can use this diagram to figure out
where the electrons live in sodium and where they live in chlorine. Ok first thing we've got to do is we've got
to find out how many electrons there are in these two atoms. Ok now sodium here, you look it up on the
periodic table, it's got this 11 here. That means it has an atomic number of 11,
there are 11 protons in sodium. Now remember when ionic bonding starts, these
atoms are not yet ions. They don't have a charge. They're neutral. So that means that they have the same number
of protons and electrons. So there are 11 protons in a sodium atom. That means there are also 11 electrons in
a sodium atom. Ok the same thing is true of chlorine. It has an atomic number of 17, 17 protons. It's starting out without a charge so it has
17 protons and 17 electrons. Now we can take one of these diagrams and
fill it in from the center on out with a number of electrons. So for sodium that's going to look like this,
11 electrons arranged around the atom from the center out. And for chlorine it's going to look like this,
17 electrons arranged around this from the center out. Now you may not be able to tell from these
diagrams but these are two very unhappy atoms. The reason why has to do with their valiance
shells. Do you remember what valiance shells are? They are the furthest out energy level that
still has electrons in them. Ok so for example this is the valiance shell
of sodium. It's got one electron here. And this is the valiance shell, the furthest
out shell, for chlorine, ok. The reason why these two atoms are so pissed
off is because every atom wants to have a full valiance shell. It's like every atoms goal in life. Sodiums really unhappy because it only has
one electron in its valiance shell and it has these seven empty spots. Ok chlorine, on the other hand, is also upset
because it's got emotionally full valiance shell but it's got one empty spot. It's so close, it's so close but it's still
super unhappy because the valiance shell isn't full. So sodium and chlorine are both unhappy. They both want to fix their situation and
in trying to fix it, that is how they're going to end up with an ionic bond. Ok so how are sodium and chlorine going to
get happier. How are they going to fix their situation? How are they going to try to fill their valiance
shells? Well take a look at this, they can help each
other out, ok. Chlorine has one spot left before it's able
to fill its valiance shell. And so what happens is sodium can give chlorine
one of its electrons, ok. So this electron moves from sodium to chlorine
to fill this spot. Here's what we end up with. Ok let me just show you what's going on here. Ok so we got sodium, we got chlorine and this
electron up here moves between them. It leaves sodium and it goes into chlorine. Ok and now chlorine has filled this empty
spot with one of sodiums electrons. Ok so now chlorine is super happy. It has a full valiance shell. It's achieved its goal in life. But take a look at sodium over here. Though you may not know it, sodium has also
achieved its goal in life because when it gave this one electron, when it gave the electron
to chlorine, it totally emptied out this valiance shell. Now you might think, ok that made it even
worse because now it has eight empty spots it has to fill. But here's the thing, if you can get rid of
all of the electrons in your valiance shell, it's like that valiance shell just disappears. Sodium doesn't even have to worry about it
anymore. Ok so it gave away its last electron in its
valiance shell and now it's like the valiance shell just disappears and this is now sodiums
new valiance shell. And check it out, it's totally full. So by giving away that one electron, it could
get rid of its whole outer shell and this is its new valiance shell. It's full and sodiums happy. So this is what we end up with. Let me just show you what the intermediate
steps look like here. And this is what it looks like when sodium
gave it away and you can sort of think about it still having this outer shell and here
is chlorine with the new electron from sodium. So we've got step one, step two, step three. Ok so now chlorine has a full valiance shell,
now sodium got rid of its old valiance shell and its new valiance shell is totally full. They're happy. But let's talk about what's going on with
the electrons here, ok, because there're electrons moving. Now over here with chlorine, it used to have
17 electrons and then it got a new electron from sodium. So it doesn't have 17 electrons anymore. Now it has an extra one so it has 18 electrons. But it has the same number of protons because
we weren't moving protons in this example, ok, so it's still got 17 protons and it's
got 18 electrons. But now there's an imbalance between the number
of protons and electrons. It doesn't have the same number of protons
and electrons anymore. It has more electrons which means that it
has a negative charge. It has a negative charge of one minus because
it has one more electron that it got from sodium. And now we can call it an ion. Now sodium also became an ion. Right, it used to have 11 protons and 11 electrons,
the same amount so it used to be neutral. But not anymore because it gave away one of
those electrons so now it only has 10. But it's still got the same number of protons. It's got 11 protons with positive charge and
it's got more protons than electrons. One more proton. And that means it's going to have a positive
charge, ok. It's going to have a one plus net charge and
it also is going to be an ion, an atom with a charge. So this guy over here has a one minus charge,
this guy over here has a one plus charge. Now as we've said before they have opposite
charges so we can maybe kind of zoom out a little bit and take a look what these atoms
are going to look like. We've got a chloride with a negative charge. We've got sodium with a positive charge. And they're going to stick together, just
like we've shown here. And that is because opposite charges, oh,
opposite charges attract. We have the positively charged sodium attaching
with a negatively charged chlorine and that's going to give us sodium chloride. Now the formation of ionic bonds is one of
the trickiest concepts in all of chemistry. So many people are confused by it. So I just want to go through this one more
time really quick, step by step. Ok so we start out with sodium and chlorine. They are both neutral. They have the same number of protons and electrons
but they're both unhappy because their valiance shells are not full. Chlorine has an empty spot and sodium has
only one electron valiance shell. So the electron here moves from sodium to
chlorine. Ok so now chlorine has one more. It has a full valiance shell and it's happy. Sodium empties out its valiance shell so it's
almost like that old valiance shell just disappears. We end up with this and a new valiance shell
is totally full. So now sodium and chlorine are both able to
get full valiance shells. But electrons had to move in this process. So now sodium has one fewer electron than
proton so it gets a one plus charge, chlorine got one more electron so it has one more electron
than proton so it has a one minus charge. So these guys, they trade electrons, or an
electron moves from sodium to chlorine, in order for them to get full valiance shells. And it's in the process of that happening
that they end up getting charges. As I said, this is one of the most complex
topics in chemistry. People have so much trouble with it. So I urge to maybe check out this video again,
watch it from the beginning, make sure you really understand it before you move on. And once you're good with this stuff, go on
to the next video.