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You might be wondering why I spent one minute
showing you pictures of food ***. Like a
delicious, sinful, pepperoni pizza, or a
delicious, wonderful chocolate cake.
Here's the connection.
What is a pizza made of?
A pizza is made of pizza base, pizza sauce, mozzarella cheese
and pepperoni.
The same way, what is a cake made of?
A cake is made of
water, sugar
butter,
eggs, and a
lot more things, like cocoa powder,
and things that I don't care to name. The same way,
ask yourself this question:
What is the world made of?
Well, if you've studied up to middle school, you'll know that the world is made of atoms.
An atom is often defined as the building block of matter. Well,
no surprise there, because we just said that the world is made up of atoms.
So, an atom
really consists of a proton,
which is a positively charged particle,
an electron, which is a negatively charged particle, and a
neutron, which,
like its name, is neutral.
The concept of charges in an atom really baffles me sometimes.
I mean, what does it mean
that a proton is positively charged? Does it have any good qualities that
makes it
the "good guy"? Or, does an electron have some bad qualities that makes it the
"bad guy"? Or, wh..wha...What about a neutron? What does....
What does the neutral charge signify?
So, when I
did some research, I came up with
the following explanation.
When scientists were discovering and exploring the micro-world,
which means the atoms and subatomic particles,
they came up with three types of particles: protons, neutrons and electrons. But that
time, they didn't actually name them that.
They just said that there were three types of particles.
One had one charge, another had another charge, and one did not exhibit any
charge - which is why it took more time to explore and find the existence of a
neutron.
So, they said that one type of charge should be
named a proton, which has a positive charge.
And they said that the oppositely charged particle would be named an....named an
electron,
which has
and negative charge. And, the neutron has no charge,
so it'll be a neutron.
So,
they did not really
have any characteristics in mind when they named that, so, the concept of positivity and negativity is
very arbitrary.
If they had named the proton as having a negative charge, and the electron as
having a positive charge,
we would have followed the convention today, and I would have said that the proton carries a
negative charge and an electron carries a positive charge,
or any
combination whatsoever.
So far we know that an atom is comprised of protons, neutrons and electrons. But where do
these things exist within the atom itself?
Well, when the scientists did a lot of experimentation and, and research, they
realized that all the positive energy of the atom is focused at its centre.
This means that all the protons are
huddled up at the centre of the atom...but wait.
Isn't there a law of science that says
"Like charges repel each other"? Well,
if all the protons are huddled up at the centre of the atom
together, that would mean that we are defying the laws of Physics and the laws of Chemistry and the
laws of nature! And that's not possible, right? I mean, we're not that
stupid.
So, this is where the neutrons come in.
The neutrons sort of
possess this charge and they possess this force that...that
binds all the protons together and they sort of intermingle and co-exist at the
center of the atom. And they together form the nucleus. So, the nucleus is comprised of
protons and neutrons. So,
the nucleus contains this strong nuclear
force that
binds all the protons together.
So, since there is an external force acting on the protons, the
repulsion is not as much and the protons are able to co-exist.
What about the electrons, then? The
electrons exist in "shells" or "energy levels" around the nucleus. And they
orbit around the atom. But,
one big misconception is that
these shells or orbits or energy levels are
somehow a
definition of the path that
the electron is going to follow
But that's a
BIG and
it's, in fact, the biggest sin a chemist can commit
because an electron is the most unpredictable thing that
a chemist will ever encounter. And,
it's not possible for anybody to really
predict where, at a given time, where you can find an electron. So,
the shell and the energy level are
more of a probability region than a...a real
real path
that the electron follows.
So, if,
for a given
probability region, or
for a given
shell, or for a given energy level,
you can find the electron
anywhere
within that region. It doesn't have to be on the periphery, it doesn't have to be
on the shape itself.
That's one big misconception that you need to get rid of right now if you want to
have any future career in...
as a chemist -
that an electron does not follow a specific path. You can only
give a probability region of
where you'll find a given number of
electrons. I think I've given you
enough information to keep you busy for a while.
So, a little recap before we end this session:
We know that atoms are "building blocks of matter".
We know that an atom consists of subatomic particles:
protons, which are positively charged, electrons that are negatively charged,
and neutrons that have been no charge. We learned that the concept of positivity and
negativity is very arbitrary and
it could've been named the
other way as well. And, we learned, finally,
that the protons and neutrons exist in the nucleus
at the center of the atom,
and the electrons
move in "shells" or "energy levels" around the nucleus.