Periodic Table
8.5C interpret the arrangement of the periodic table, including groups and periods, to explain how properties
are used to classify elements
For these notes you will need:
Before we really begin – what are elements (again)?
Substances that cannot be separated into simpler substances by chemical means
So how do we know if this is an element?
What about this substance?
Elements are identified as 1 substances represented by 1-2 letters and can
be found on the Periodic Table. We will add to this understanding as we
learn in this unit.
This leads us to: How are elements arranged on the PT?
A Little Periodic Table
History…
History of the Periodic Table
• Dmitri Mendeleev, a Russian scientist
born in Siberia in 1834, is known as the
father of the periodic table of the
elements
• The periodic table is designed to help
you predict chemical and physical
properties of elements
Key points are
underlined, you
might want to write
them down!
Video: The PT or Mendeleev’s work
Get out your Periodic Table and (colored) pencils
How to “Read” the Periodic Table: Step 1
View the periodic table as starting at the top left and ending at
the end of the last row, near the bottom right.
The table is structured from left to right in order of increasing atomic number.
The atomic number is the number of protons in a single atom.
Not every row or column is complete. Although there may be breaks in the
center, reading the table will continue from left to right. For instance, Hydrogen
has an atomic number of 1 and it is in the top left. Helium has an atomic number
of 2 and it is in the top right.
Elements 57/58 through 103 are usually pictured as a subset at the bottom right
of the table. These are the “rare earth elements.”
Look for
increasing
atomic
number
pattern
How to “Read” the Periodic Table: Step 2
Find a “group” of elements in each column of the table. There are 18
columns. Sometimes groups are referred to as “families”.
• A column of elements is called a group. Groups describe elements that share
common properties, usually based on the number of valence electrons
• Numbering will usually be above the columns; however, it may appear below
some groups, such as metal.
A look at the second column, or group:
If you looked at one atom
of every element in this
group you would see…
Each atom has the same number of
electrons in it’s outermost shell.
How do I know that??
Think back to the Bohr Model…
The group 2 elemental atoms all have 2 electrons in their
outer shells:
Be (Beryllium)
Atom
Mg (Magnesium) Atom
Valence Electrons
• Effect the way an atom bonds, which determines many of the
chemical properties of the element, including reactivity
• Remember, Atoms can have anywhere between 1 and 8 valence
electrons
• This is why elements within a group usually have similar chemical
properties – because valence electrons govern how an element will
react with other substances
Check point!
Potassium has properties most similar to which of these
elements?
• Lithium (Li)
• Beryllium (Be)
• Calcium (Ca)
How to “Read” the Periodic Table: Step 3
Find a “period” of elements in each row of the table.
• There are 7 periods.
• The periods are usually numbered 1 through 7 on the left hand
side of the table.
• All of the elements in the same period have the same number of
atomic shells (the area that the electrons live in)
• Each period is bigger than the last. This is associated with
increasing energy levels of atoms on the periodic table.
How to “Read” the Periodic Table: Step 4
Understand additional grouping according to metal, semi-metal
and non-metal.
All of the groups are shaded differently so you can tell them apart.
• Elements are located in three main categories on the periodic table based
on their physical properties
• Metals
• Nonmetals
• Metalloids
• Shade these now on your PT
Physical Properties
• Physical properties can be observed or measured without changing the
composition of matter.
• Physical properties are used to observe and describe matter.
• Examples are color, odor, shape, size, density or mass
Examples of Physical Properties
Mass – How much matter
is in an object
Malleable – Can be pounded/rolled
into a shape
Density – How tightly mass is
packed into an object
Color/Texture
Ductile – Can be stretched
into a long wire
Metals
Metal Trends shown on the PT:
1. In METALS reactivity DECREASES as you go ACROSS a Period because
though they still want to give away valence electrons they have more of them
to get rid of, which requires more energy.
2. DOWN a Group: In
METALS reactivity
INCREASES as you go
DOWN a Group because the
farther down a Group of
metals you go, the easier it
is for electrons to be given
or taken away, resulting in
higher reactivity.
Metals
Most elements are metals. The 88 elements to the left of the
stairstep (or zig-zag) line are metals or metal-like elements.
Physical Properties of Metals:
– Luster (shininess)
– Good conductors of heat and
electricity
– High density (heavy for their
size)
– High melting point
– Ductile
– Malleable
Video on PT and Metals
• https://www.youtube.com/watch?v=0pdRxrmgRoQ
Check Point Question!
When you crush a steel can for recycling for stomping on it, it collapses
down but does not fall apart or shatter. What is the best explanation for
this?
A. When force is applied the metal undergoes its brittle property
B. When force is applied the metal is malleable and can be re-shaped
C. When force is applied the metal undergoes its ductile property
D. When force is applied the new shape makes it easier to recycle
Nonmetals
Nonmetals
Nonmetals are found to the right of the stair-step line. Their
characteristics are opposite those of metals.
• Physical Properties of Nonmetals:
• No luster (dull appearance)
• Poor conductor of heat and electricity
• Brittle (breaks easily)
• Not ductile
• Not malleable
• Low density
• Low melting point
Metalloids
Metalloids
Elements on both sides of the zigzag line have properties of
both metals and nonmetals. These elements are called
metalloids.
Physical Properties of Metalloids:
• Solids
• Can be shiny or dull
• Ductile
• Malleable
• Conduct heat and electricity better than nonmetals but not
as well as metals
Chemical Properties
•
A chemical property is a characteristic that is observed
when a substance changes into a different substance.
Examples of Chemical Properties
Combustible – capable of
igniting at higher temps
Corrosion –
destruction of
metals
Reactivity – undergoes a
chemical reaction
Oxidation – rusting or tarnishing
Flammable – capable of
igniting
Back to the PT: Each group has distinct properties
• The periodic Table is divided into several groups based
on the properties of different atoms
For example…
A closer look at the groups:
Metals!
Alkali Metals
Soft, silvery colored
metals
Very reactive!!!
Reactions with water!
• https://www.youtube.com/watc
h?v=uixxJtJPVXk
Alkaline Earth Metals
Silvery-White
Metals
Fairly reactive
Many are found in
rocks in the
earth’s crust
Transition Metals
Most are good
Conductors of
electricity
Malleable (easily
bent/hammered into
wires or sheets)
Metalloids lie on
either side of these
“stair-steps”
The Metalloids are:
Boron
Silicon
Germanium
Arsenic
Antimony
Tellurium
Polonium
They share properties with
both metals and non-metals
Si (Silicon) and Ge
(Germanium) are very
important “semi-conductors”
Semiconductors:
What are semiconductors?
Semiconductors are used extensively in electronic circuits. As its
name implies, a semiconductor is a material that conducts current,
but only partly. The conductivity of a semiconductor is somewhere
between that of an insulator, which has almost no conductivity,
and a conductor, which has almost full conductivity.
Semiconductors:
https://www.youtube.com/watch?v=u3GdpbKTPQQ
Nonmetals
Brittle
Do not
conduct
electricity
Halogens
Most are Poisonous
Salt Forming
Fairly reactive
Noble Gases
Unreactive
Gases at room
temperature
Exist in Earth’s
atmosphere
Jellyfish lamps made with noble gases
What are the Noble
gases?
https://www.youtube.
com/watch?v=jdzBRm
LsUM8
https://www.youtube.
com/watch?v=qNaBM
vJXdJ4
Activity!
Make sure you have:
• Element cards
• Instructional worksheet and
cards
• Notebook
Before you begin, title the page in
your notebook - “PT Practice”
• On the same page, draw the
carbon square and identify the
parts shown form the
instruction page. Use this as a
guide to help you ID the other
elements
Work as a table group!
To complete activity:
Pick 4 different types or categories of elements and write
down the information about these in your notebook.
For example, pick a metal, a semiconductor, a gas, etc.
When your group is done, pick up the activity and return it to
the counter.