So now that we've explored covalent bonds,
the very strongest of biological bonds
let's take a look at ionic bonds. Common table
salt or sodium chloride is a result of a formation
of ionic bonds. Ionic bonds result from first,
creating an ion by stealing an electron from one
and then the resulting charge of a positive and
negative sticking together. So they are less strong
than a covalent bond. That's still fairly stable.
I think of this as an example of, say that
having a full electron shell is like having all
of the clothes on that you need, eight electrons.
And having not so full electron shell is sort of
like that you would want to have another item
of clothing on. Say I'd like to put my jacket on.
So, in this case we have sodium which actually has
one valence electron. It could easily drop that
valence electrons they had and be very happy
with a regular set of clothes. Or it could gain
seven more electrons which is particularly difficult.
So in this case, it's actually more willing to
give up one electron. So now, let's take a look
at chlorine. It's the perfect pairing for sodium.
It has seven valence electron and space to gain one.
Again, it wants to be fully clothed. So it's going
to run on over to sodium. It's going to grab the
extra electron on the outside and put in on itself.
Now sodium is quite angry. And so sodium is
going to run after chlorine and try to get its
item of clothing back. Say its jacket.
Because sodium is chasing down chloride, they're
going to stick together. So the positive charge
of sodium and the negative charge of chlorine lends
itself to them, sticking together and forming
a crystalline structure. So when chlorine steals
the electron from sodium, it satisfied the octet rule
and also left sodium satisfied because it also has
a full valence shell. Both of these molecules
are now stable when they are in association. So
when we stir our sodium chloride into a glass of water,
the sodiums and the chlorides are literally falling
apart because of the ionic charges. And shortly,
we'll start to understand how water dissociates
and polarity of different molecules such that
sodium and chloride can actually
become dissolved in water.