An introductory presentation to the periodic table I gave to my children's 5th grade classes. If you enjoy it, please, use it in your own class, if you are a teacher, or, use it to give a similar talk at your children's elementary school.
2. Let’s start with a song …
So who can explain
the periodic table for
me now?
3. Hmmm … let’s start at the very beginning
What is the purpose of the Periodic Table?
To summarize and predict the chemical
properties of real elements
4. Now for a bit of history and fun facts …
Russian chemistry professor
Dmitri Mendeleev published
the first periodic table in 1869
Carbon is unique in
that it is known to
form up to 10 million
different compounds.
Francium is the rarest
element on earth. Only a
few ounces of it on earth
at any given time.
The country Argentina is
named after the element
silver (symbol Ag) which
is argentum in Latin.
The only letter not in the
periodic table is the letter J.
Each element has its own name
and abbreviation Some of them
are easy to remember, like H for
hydrogen. Some are a bit harder
like Fe for iron or Au for gold.
5. Actual picture of a Hydrogen Atom
To understand the Periodic Table, we need to understand …
What is an Element?
An element is an Atom …
such as Hydrogen or Helium
An atom has a Shell
= 1 Electron for Hydrogen
Just so you know ….
Electron has a negative charge
(flows though electric cables)
Proton has a positive charge
An Atom is ALWAYS electrically
neutral (no charge)
Hydrogen Size = 53 x 10^-12 m
An atom has a Nucleus
= 1 Proton for Hydrogen
Radius = 10^-15 m
= Super Tiny!
To compare … A hair is about a Billion
times larger than Hydrogen atom
6. What is the Nucleus good for?
The nucleus is the center of an atom The nucleus has most of the mass
of an atom, though it is only a very
small part of it
The nucleus is made up of
protons (positive charge) and
neutrons (no charge)
Rows of the periodic table
are organized by increasing
atomic number. And each row
is called a period
The nucleus is held together
by the nuclear force
The atomic number is
equal to the number of
protons in the atom
7. Again … The Rows or Periods of the periodic table count
the number of protons in an atom!
8. What is the Shell good for?
The Shells of an atom hold
the electrons
The number of electrons determine
which group of the periodic table
an atom belongs to
The number of electrons in
the outer shell (a shell that
is not filled) determine the
chemical properties of an
element
If a shell is filled (for example
2 electrons in the K shell), the
element does not react with
other elements. It is called
stable!
The less electrons in a
shell, the more chemically
reactive an element is
9. Again … The group of an element is determined by the
number of electrons in its outer shell
Alkali Metals
are the most
reactive
elements!
Why?
What do
they have in
common?
10. Why is the periodic table periodic? Let’s look at a Group …
Hydrogen
Lithium
11. Why is Hydrogen and Lithium in one Group?
Hydrogen and Lithium and all the other elements in the Alkali Metal
Group have a single electron in their outer shell
12. Now the TEST!!!!!
Nobel Gases
are the least
reactive atoms
Why?
What do
they have in
common?
13. Wait … one more … a trick question …
Why does the
1st period only
have Hydrogen
and Helium?
14. Can you now predict what happens?
Oxygen misses 2 electrons to make its outer shell complete!
It takes the electrons from Hydrogen, as it has a stronger electric force
(more electrons) than Hydrogen! But it is not strong enough to kick the
Hydrogen nucleus away