Hi. It's Mr. Andersen and this chemistry essentials video 20. It's on ionic
Hi. It's Mr. Andersen and this chemistry essentials video 20. It's on ionic

bonding. Remember ionic bonding differs from covalent bonding. In covalent bonding they're
bonding. Remember ionic bonding differs from covalent bonding. In covalent bonding they're

sharing the electrons. In ionic bonding what you're doing is you're transferring the electron
sharing the electrons. In ionic bonding what you're doing is you're transferring the electron

from one atom to another. And so the quintessential example is sodium chloride. So sodium, here's
from one atom to another. And so the quintessential example is sodium chloride. So sodium, here's

its electron configuration, has 1 valence electron. And chlorine is going to have 7.
its electron configuration, has 1 valence electron. And chlorine is going to have 7.

And so if we look at their electron configuration, if we can actually transfer that electron
And so if we look at their electron configuration, if we can actually transfer that electron

from sodium to chlorine, then we get to this electron configuration that is a nobel gas.
from sodium to chlorine, then we get to this electron configuration that is a nobel gas.

It's going to be very stable. And so what we get is a sodium ion and a chlorine ion.
It's going to be very stable. And so what we get is a sodium ion and a chlorine ion.

And so the sodium ion, since it's lost an electron, we call that a cation, it has a
And so the sodium ion, since it's lost an electron, we call that a cation, it has a

positive charge. And the chlorine is going to be a negative charge. And the way I remember
positive charge. And the chlorine is going to be a negative charge. And the way I remember

this, it's a little bit silly, but if you take that sodium ion, a cation, if you think
this, it's a little bit silly, but if you take that sodium ion, a cation, if you think

of a cat, a cat has paws. And that means it's positive. Sorry about that. That's a little
of a cat, a cat has paws. And that means it's positive. Sorry about that. That's a little

bit lame. But it's a good way to remember it. And so an ionic bond is going to be between
bit lame. But it's a good way to remember it. And so an ionic bond is going to be between

ions. It's a connection between ions. And so we're going to have a cation and an anion.
ions. It's a connection between ions. And so we're going to have a cation and an anion.

Cations are going to be positive. That means they've lost an electron. And anions are going
Cations are going to be positive. That means they've lost an electron. And anions are going

to be negative. And so what they form is something called an ionic solid. Now how well that solid
to be negative. And so what they form is something called an ionic solid. Now how well that solid

is held together is based on Coulomb's law. Remember, if we have a larger charge there's
is held together is based on Coulomb's law. Remember, if we have a larger charge there's

going to be a larger attraction between those two molecules or atoms in this case. And then
going to be a larger attraction between those two molecules or atoms in this case. And then

the greater the distance is the less the force is. And so if we have a really small ion and
the greater the distance is the less the force is. And so if we have a really small ion and

a large charge, we're going to have a stronger interaction. So it's important to kind of
a large charge, we're going to have a stronger interaction. So it's important to kind of

remember those two things. And so here's sodium chloride then. Sodium chloride is going to
remember those two things. And so here's sodium chloride then. Sodium chloride is going to

be all of our sodium ions. Those are going to be purple which have a positive charge.
be all of our sodium ions. Those are going to be purple which have a positive charge.

And they're going to organize themselves in this real crystalline nice solid. It's really
And they're going to organize themselves in this real crystalline nice solid. It's really

high melting point. High boiling point. The super easy way to break it apart is with water.
high melting point. High boiling point. The super easy way to break it apart is with water.

But it's going to be an incredibly stable kind of a molecule. And so what determines
But it's going to be an incredibly stable kind of a molecule. And so what determines

the stability, how well it's held together? It's simply Coulomb's law. Coulomb's law remember
the stability, how well it's held together? It's simply Coulomb's law. Coulomb's law remember

if we have the same charge there's going to be repulsion. And if we have opposite charges
if we have the same charge there's going to be repulsion. And if we have opposite charges

there's going to be attraction. But if we look at the formula, the bigger those charges
there's going to be attraction. But if we look at the formula, the bigger those charges

are, the greater that attraction is. And the bigger the distance, since this is the radius
are, the greater that attraction is. And the bigger the distance, since this is the radius

right here, the less that attraction is going to be. So let's throw sodium chloride up here.
right here, the less that attraction is going to be. So let's throw sodium chloride up here.

Sodium, which is going to be the cation. Chlorine which is going to be the anion. And then there's
Sodium, which is going to be the cation. Chlorine which is going to be the anion. And then there's

something called lattice energy which just is a way to measure how well this lattice
something called lattice energy which just is a way to measure how well this lattice

is held together. And so if we look at this right here, I mean, make a prediction. What
is held together. And so if we look at this right here, I mean, make a prediction. What

do you think is going to happen when we move this from sodium chloride to sodium fluoride?
do you think is going to happen when we move this from sodium chloride to sodium fluoride?

Well in each of these diagrams here sodium is going to be this little purple sphere.
Well in each of these diagrams here sodium is going to be this little purple sphere.

And I've tried to keep that about the same size. But let's look at fluorine now. As we
And I've tried to keep that about the same size. But let's look at fluorine now. As we

move to fluorine, can you see that that fluorine ion is going to be smaller? And since it's
move to fluorine, can you see that that fluorine ion is going to be smaller? And since it's

smaller our lattice energy is going to increase because those ions are closer together. So
smaller our lattice energy is going to increase because those ions are closer together. So

let's go back to sodium chloride. What do you think is going to happen when we make
let's go back to sodium chloride. What do you think is going to happen when we make

sodium bromide? Well the purple sodium cation is going to stay the same, but now since we've
sodium bromide? Well the purple sodium cation is going to stay the same, but now since we've

increased the size of that atom, we've decreased this lattice energy. Same thing as we go to
increased the size of that atom, we've decreased this lattice energy. Same thing as we go to

sodium iodide. And so as it gets bigger, that distance between the two, just due to Coulomb's
sodium iodide. And so as it gets bigger, that distance between the two, just due to Coulomb's

law, we're going to see a decrease in that energy between them. But what's the other
law, we're going to see a decrease in that energy between them. But what's the other

thing that can affect it is the charge. So if we run sodium chloride versus barium oxide
thing that can affect it is the charge. So if we run sodium chloride versus barium oxide

which is going to have a totally different charge, you can see that there's a great difference
which is going to have a totally different charge, you can see that there's a great difference

between those lattice energies. In other words as we increase the charges, we increase that
between those lattice energies. In other words as we increase the charges, we increase that

ionic bond between the two atoms. And so did you learn this? To connect the microscopic
ionic bond between the two atoms. And so did you learn this? To connect the microscopic

structure to the macroscopic properties? It's simple. It's Coulomb's law. The greater the
structure to the macroscopic properties? It's simple. It's Coulomb's law. The greater the

charge is and the smaller the distance between the ions, the greater the bond strength. And
charge is and the smaller the distance between the ions, the greater the bond strength. And

I hope that was helpful.
I hope that was helpful.