The Periodic Table of Elements
How to understand the layout of the P.Table and to know what
elements are in the first place…
#1 What are “elements” anyway?
You probably recognize the name of many elements on the Periodic
Table. Oxygen, Calcium, Iron, Gold…they’re all on there.
But why isn’t water on the Periodic Table? Or brass? Or cookie
dough? Because…
The 100+ elements on the periodic table are all pure substances made
of just one kind of atom.
Let’s see what that really means.
#2 Joe and Janet
Joe’s got some water
Janet’s got some gold
They agree to give each other an ITSY little bit of what they’ve got
#3 Joe and Janet Share!
Janet takes her gold and, using the smallest knife you can ever
imagine, she cuts her gold bar in half. And then in half again. And
again. Over and over and over until she’s left with a tiny little bit
that she can’t cut in half any more.
So she gives to Joe one single gold atom. It does exactly the same things
as the huge gold bar she started with, but it’s just a whole lot smaller.
Gold is an element. It’s made of one kind of atom,
different from calcium or silver or helium.
#4 Joe’s turn!
Joe’s happy with his gold atom. He wants to give Janet a water atom.
So he uses the tiniest little spoon you can imagine, and scoops away
half his water. Again and again and again. But he finally gets to a
point where…
He’s left with 3 atoms…one oxygen
atom and two hydrogen atoms stuck to
each other. (Now H2O makes sense)!
Joe borrows Janet’s knife and chops
into this itsy bitsy water drop. As he
makes his final cut, the water drop falls
apart and the 3 atoms drift away into the
air. Joe is sad that he has nothing to
give to Janet.
#5 So that means that Water…
…isn’t an element. Sure, it’s a pure substance, but it’s made FROM
elements, specifically hydrogen and oxygen. That’s why you can’t
find “water” on the Periodic Table. It’s the same reason why you won’t
find “yogurt” or “dirt” or “puppy” on there, either.
So…gold is made up of just ONE kind
of atom…gold atoms! ELEMENT!
And water is made up of different kinds
of atoms stuck together. NOT an element!
So everything in the universe made of matter is either
a chunk of element, or is made FROM several elements! Yeah!
#6 So what makes a Gold atom
different from, say, a Platinum
atom?
This is a big deal in 8th grade science…learning how the elements
are made from different kinds of atoms. Here’s the quick & easy
6th grade answer:
You’ve seen pictures of atoms like this for years
in science books and videos.
The 100+ elements of the Periodic Table each
have a different number of Protons (the yellow
spheres in this model), which are just parts inside
an atom. Next year, you’ll learn more about this.
#7 Elements…
Aluminum foil is made entirely from element #13, Aluminum!
But “steel” is made from a combination of iron and carbon.
Steel
isn’t an
element.
#8 Let’s get this thing sorted…
Back in the 1800s, scientists knew of about 50 or 60 elements. It was
confusing trying to keep track of all of them, and how they were alike
and different, so several scientists set about trying to organize the
elements in a useful manner.
This guy, a Russian named Dmitri Mendeleev, succeeded. He wrote
down information about the known elements, then put them together
in alike groups.
He figured if he could arrange alike elements in
columns, with the “lightest” ones at top and “heaviest”
ones at bottom, he’d make a nice, nifty chart.
#9 Mendeleev’s P. Table
His chart had a ton of holes
in it where he predicted new
elements would be
discovered. He could
predict a lot of things about
the missing elements,
because they would be alike
the elements around them.
Mendeleev arranged his periodic table by atomic mass, or how “heavy”
the atoms of that element are. His P.T. has trends and patterns for both
the columns up and down and rows left and right.
#10 Review
•Elements are pure substances made of just one kind of atom.
•Everything else is made FROM elements combining together.
•Dmitri Mendeleev arranged the elements into the Periodic Table.
•In the P. Table, elements in the same column are very similar (alike).
•Elements in the same rows also share certain properties.
#11 “Groups” of Elements
We’re going to break down the Periodic Table into 3 big groups and
color code it.
That’s good news, because we
could get a lot more technical
and have 9 or 10 groups instead.
Be sure to color LIGHTLY so that you can still read the information
on your paper. LIGHTLY.
Your name!
Nonmetals
Metalloids
Metals
#13 What makes those 3 groups
different?
Metals, nonmetals and metalloids differ in their physical & chemical
properties (observable characteristics). We’ll learn much more about
that stuff a little later.
#14 One More Thing…
“What’s up with those two rows
at the bottom?” is an often-asked
question.
It’s just a way to get the Periodic Table to fit on a normal-sized piece
of paper. The way it should REALLY look is like this:
#15 And that is…
…until we see in a few days how metals, nonmetals, and
metalloids are different.