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Hey guys, so the purpose of this screencast is to express the fundamental differences
between ionic vs. molecular compounds and I picked just two examples here. Here is an
ionic compound known as sodium chloride and here is a molecular compound, um, known as
glucose. In other words we'll just call it sugar. So, one of the fundamental differences
that I'm going to talk about is what happens when they're placed in water. So as you
drop some amount of sodium chloride in water, it sticks together the whole way and then
all of a sudden when it gets into water, um, something noticeable changes and we can't
see it with our eyes but we can represent it in this simulation. It changes, or it separates
into its ions. Okay? And what I mean by that is it has a bunch of sodium ions that are
positively charged and it has a bunch of chloride ions that are negatively charged. Okay so
it goes from this nice solid structure here to separating into its ions. If you try to
do the same thing with sugar and drop some amount of sugar in there, what you would notice
is that if you could see it at the molecular level, the sugar molecules actually stay together.
So they were like this before and they're also like that afterwards, OK, so they stay
together. So what you see is there's no charge on these, they're all neutral and
they kind of just stay together whereas the ionic ones split up into their own charges.
Another fundamental difference between the two is the composition of them. Ok, so if
you have sodium, so this is sodium and this a chloride ion, so sodium chloride, what you
notice is that sodium, according to this periodic table, sodium is considered to be a metal
right here. So we can dub sodium as a metal whereas chlorine, as seen on the periodic
table, chlorine is over here, it's considered to be a nonmetal. And this is the general
trend for all ionic compounds. At least the majority of them. Made up of metals and nonmetals.
If you look at the composition of sugar, or in our case glucose, what you notice is that
it's made up of carbon atoms, hydrogen atoms, and oxygen atoms. If you look at the periodic
table, hydrogen is a nonmetal, carbon is a nonmetal, and oxygen is a nonmetal. So what
we can do is classify these as all nonmetals and this is one of the fundamental characteristics
of for the majority of molecular compounds is that they're composed of nonmetals. Alright,
the last, uh, difference I want to show you is if you were to place each one in water
and then put some sort of conductivity meter in there and so what you kind of have to pretend
is we have 2 beakers of water and one of them we have our sodium ions floating around and
we have the chloride ions floating around full of negative and positive charges. Ok,
what you would notice is if you put some sort of conductivity probe in there with two electrodes,
um, and then they have some sort of casing or a battery and then from that, maybe you
have some sort of light bulb, it's a beautiful light bulb, um, what you notice is the light
bulb actually, when it's turned on, um, and placed in this solution, the light bulb
actually starts to emit some light. Ok, so the big thing to take away here is that what
that means is that ionic solutions are conductive. By conductive I mean they can allow electricity
to pass through. A solution full of ionic, that has ionic compound dissolved in it, because
of its ions being charged floating around, um, migrating from one electrode to the other,
ok, um, essentially bridge this gap right here and allow electricity to pass through
and therefore this light bulb to light up. If you try to do the same thing with sugar
molecules involved and let me place sugar in there. If you try to place this conductivity,
same conductivity meter in this, um, sugar filled solution, because the molecules of,
um, sugar are all neutral and they don't have a charge on them like the ions here,
um, no light is going to be emitted on this light bulb. Ok so, what you can say is that
it's not conductive. In other words, when molecular compounds are dissolved in water,
um, they don't allow electricity to pass through for the most part. And so we consider
them to be non conductive. And so those are 3 fundamental differences between ionic compounds
and molecular compounds.