Transcript What good is the Periodic Table?

What good is the
Periodic Table?
There is a table provided for your
use during the TAKS test, what
can it do to help you?
What is an element?
• Basically, if it is listed anywhere on the
periodic table (of the elements) it is an
element.
• If it is on the left side it is a metal element,
if it is on the right side it is a NONmetal
element. (Hydrogen is the ONLY
nonmetal to the left of the stairstep line.)
• Let’s look . . .
Where are the metal elements?
Left of the Stair-step line!
Where are the nonmetals?
To the Right of the stair step line, and Hydrogen!
Where are the metalloids?
Along the stair
step line.
These
elements have
properties of
both metals and
nonmetals.
The center elements on the table are called the
transition metals. Many of them have more than 1 way
they will give away electrons, so they change, or
transition, ion charges. The charge these metals use
are given by a roman numeral in the name. (Iron (II)
chloride)
The Rare Earth Metals are radioactive and
form the bottom 2 rows, also called the
Lanthanide and Actinide Series.
So, I can tell if it’s a metal or not,
what else?
• Each column on the table is a group or
family of elements that have similar
chemical properties.
• They form the same types of compounds,
in the same ratio.
• They have the SAME NUMBER OF
OUTER SHELL (valence) electrons.
• Lets look . . .
Group # 18 is the family called Noble Gases
– each one has 8 outer shell electrons (full
shell) so they don’t form compounds.
Group #1 is called the Alkalai metals,
they have 1 valence electron, and will
form +1 ions. The are Alkalai because
they form the strongest (highest pH)
bases.
Group #2 is called the Alkalai Earth Metals
and they have 2 valence electrons, which
they will give away to form +2 ions.
Group #17 are the Halogens, they all have 7
electrons in their valence shell, and want to
have 1 more when they form compounds.
They all become -1 ions when they can.
For each group, they form compounds
the same way, for example. . .
• Beryllium forms a compound with Cl in the
ratio of 1:2 or BeCl2
• Since Mg and Ca are in the same family or
group, they will form the same type of
compounds in the same ratio.
• MgCl2 and CaCl2
• This is what is meant when they have
“similar chemical properties”
Each square also tells us
information about each element.
• The 1 or 2 letters that
represent the element
are its symbol.
• The number at the top
of the square is the
atomic number.
• The numbers at the
bottom of the square
is the average atomic
mass.
What do the numbers mean?
11
Na
22.990
sodium
This is the atomic
number. It is the number
of protons in a single
atom of this element. By
the way, its also # of
electrons.
The symbol for this element.
This is the atomic mass, it is
the number of protons +
neutrons, or the mass of the
nucleus of an atom.
This is the name of the element.
Use the table, it will help you
answer at least 5 questions!
That may be the difference you need to pass!!
Now, let’s write some
formulas and names
1. Roll one of each color, the positive
ion is written first.
2. Use the charge as the subscript to
the opposite ion, but remove the + or
--.
3. If the ion is a group, DO NOT
CHANGE THE GROUP, put it in ( )
with the number as a subscript
outside.
4. To name it, write the name of the +
ion, then name the – ion, or if it is an
element, change the ending to –ide.
Don’t forget the Roman Numeral for
transition metals.
Law of Conservation of Mass
• Matter can not be
created or destroyed.
• This means if it is on
one side of an equation,
it must be on the other,
and there must be the
same number of atoms
of that element.