Ever wonder where exactly did the periodic
table come from?
Well, we can think the French nobleman Lavoisier.
He was the one who basically is known as the
'Father of Modern Chemistry.'
He basically helped to predict the names of
oxygen and hydrogen and successfully predicted
the element silicon.
He was great when it came to studying patterns
in chemistry as well as biology.
And, it’s because of him, they were able
to construct a list of the first 23 elements
that would eventually lead to the periodic
table.
Now, it wasn’t until 1869, when we had Mendeleev
who used the word periodic table for the first
time.
He saw patterns in these elements.
He saw that they increased in mass over time.
And then, he saw that their electrons arranged
themselves in certain patterns, which caused
them to have similar chemical properties.
We’ll get more into this type of periodic
law, as well as electrons later on in the
semester.
But, just realize, it’s because of these
two great scientists that we have the periodic
table.
Today, we have well over 110 elements in the
periodic table, 114 and counting.
We’re going to say that a majority of them
occur naturally in our environment and there
are some that we’ve even synthesized in
the laboratories.
Now, if we take a look at the periodic table,
you’re going to have to realize that when
it comes to the periodic table, you’re going
to have to memorize a few of these elements.
Most professors will want you to memorize
the first 30 elements.
But, honestly, to be entirely safe, I would
recommend memorizing elements 1 to 36.
Now, when I say memorize, I don’t mean memorize
the symbol and all the numbers associated
with it.
That will come over time through practice
and problems.
When I say by memorize, I mean realize that
when I see Ni, what element is that?
That’s nickel.
This would be titanium, magnesium.
Memorizing the first 36 symbols will help
you in a long way to figure out what exact
element are we talking about when you’re
given a symbol.
Now, we have to realize that the periodic
table, because of the periodic law given to
us by Mendeleev, is set up this way because
it follows their reactivity in chemical properties.
We don’t need to know exactly what those
are yet, but just realize that the periodic
table is set up this way for a very good reason
because this is the way their electrons arranged
themselves.
But, what we need to know right now is exactly,
what do certain areas of the periodic table
tell us.
Now, what we should realize is that there
are basically three types of groups in the
periodic table.
There are metals, there are metalloids, and
then there are non-metals.
Now, here when we go to B, B is called boron.
And, what we’re going to do here is we’re
going to draw a staircase.
Here goes our staircase.
Now, we’re going to say on this staircase,
there’s boron, there’s the silicon, there’s
arsenic, there's Te and At, these five elements
that are on the staircase.
Right underneath the staircase are these two:
germanium and antimony (Sb).
These seven elements that I’ve highlighted
with these blue streaks, these are our metalloids.
Metalloids are called semiconductors.
What exactly does that mean?
Well, semiconductors means that they conduct
electricity.
You can run electricity through them.
Not as well as metals, but much better than
non-metals.
Metalloids are basically a blending of non-metals
and metals.
They don’t exactly fit in metal category
or non-metal category.
What they are, are kind of like a hybrid of
the two.
Metalloids are really important in industry.
Like, the computer chips that we have in our
cellphones, in our computers, in our TVs—they
come from certain types of metalloids.
They come from silicones.
Silicon chips that are in those structures,
those are metalloids.
Now, those seven are metalloids.
We’re going to say everything here in red
to the right of it, so all these guys here,
all of these guys are our non-metals.
We’re also going to say hydrogen over here,
even though it’s over here.
It’s also a non-metal.
The ones in the blue streaks are your metalloids.
The ones that are in red are your non-metals.
Non-metals tend to be brittle and dull in
color.
They don’t conduct electricity.
They don’t insulate.
They don’t hold on to heat very well.
These are the properties of non-metals.
We’re also going to say that it seems like
there’s a lot fewer non-metals because everything
else that’s not with blue streaks or not
in red is considered a metal.
As you can see there’s a lot more metals
in the periodic table than anything else.
Metals tend to be shiny.
They conduct electricity very well.
These are the properties that we’ll see
with metals.
They’re very reflective.
Gold, silver, platinum; these type of metals
is what comes to mind.
