CHAPTER 3- INTRODUCTION TO
THE PERIODIC TABLE
Miss Le- 10/17/14
Pay attention to your notes ;)
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Pop quiz at the end!
How did it all start?
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1860, Scientists had already discovered 60
elements and determined their atomic masses
Noticed some elements had similar properties and
gave a group of similar elements a name
 Ex.
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Coinage metals
Wanted to organize the elements that would show
similarities and differences at the same time
Dmitri Mendeleev’s Periodic Table
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Russian professor at the University of Petersburg
1869 published a table of elements organized by
increasing atomic mass
 Listed
elements in a vertical column starting with the
lightest
 Started another column when he reached an element
that had similar properties to another element already
in the column
 This
way elements with similar properties were in
HORIZONTAL rows
Mendeleev Cont.
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Later developed an improved version
His contribution:
 Showed
that the properties of the elements repeat in
an orderly way from row to row of the table
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This repeated pattern is an example of periodicity
in the properties of the elements
Periodicity- the tendency to recur at REGULAR
intervals
 Ex.
Halley’s comet every 76 years, full moon every 28
days, what else?
Mendeleev Cont.
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Table was widely accepted because it was, to date,
the clearest and most consistent arrangement of the
elements
Left blank spaces in the table and undiscovered
elements would eventually occupy these spaces
By noting the trends in the properties of known
elements, he was able to predict the properties of
the undiscovered elements.
Moseley
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There was inconsistency with Mendeleev’s prediction
of elements and their properties by the way he had
organized the periodic table
Moseley solved the problem of the inconsistency
between the positions of the elements and their
atomic masses
He rearranged the elements by increasing atomic
number instead!
Resulted in the structure of the modern periodic
table. Thanks, Moseley!
Periodic Law
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Atomic number increase by one as you move from
element to element across a row
Each row (except the first) begins with a metal and ends
with a noble gas
Properties of the elements change in an orderly
progression as you move from left ot right
All the trends above illustrate periodicity in the
properties of the elements
Periodic Law- the physical and chemical properties of
the elements repeat in a regular pattern when they are
arranged in order of increasing atomic number
POP QUIZ
1.
2.
How does the modern periodic law differ from
Mendeleev’s periodic law?
What are the two factors that contributed to the
widespread acceptance of Mendeleev’s periodic
table?
3.2 Using the Periodic Table
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Period- horizontal rows
Group/Family- vertical columns
 Groups
are numbered from left to right
 Ex. Lithium is the first element in group 1 and in period
2
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Have a marker handy because we’re going to be
coloring today!
 Marker-
outline instead or coloring
Noble Gases
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Please get out your periodic tables
 We’ll
label as we discover special groups of the
periodic table
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Group 18 elements are the noble gases
Remember what’s special about them?
 Hint:
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what do their outer most energy levels look like?
They’re generally unreactive because of this
Characteristics of Noble Gases: They’re nonmetals.
They’re unreactive because their outermost energy
level is completely filled.
Metals
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Metals are elements that have luster, conduct heat
and electricity, and usually bend without breaking
Metals have one, two, or three valence electrons
 Exceptions
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All metals are solids at room temp. and most have
extremely high melting points
 Exception
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are tin, lead, and bismuth
is mercury
Most metal elements are located in groups 3-12
Transition Elements/Metals
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Do you have your periodic table handy?
Let’s label the Transition Metals
 Groups
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3-12
Characteristics of Transitional Metals: Their behavior
is less predictable than the main group metals and
this is because their atomic structure is more
complicated. They also have the characteristics of
metals.
Let’s label the main group metals too!
More about Periods
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The period number of an element is the same as the
number of its outermost energy level!
 Recall
that valence electrons are located in an element’s
outermost energy shell.
 Ex. Valence electrons in the second period are in the
second energy level
 Question: Looking at your periodic tables, what period
is Aluminum in? So what energy level is it’s valence
electrons located in?
Relationship between Valence Electrons
and Chemical Properties
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You need to know the relationship between the two.
Elements in the same Group have the same number
of valence electrons, right?
Well because of this, elements in the same group
have similar chemical properties.
Summary: Elements in the same group have similar
chemical properties because they have the same
number of valence electrons.
Common Names for other Groups
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So far we’ve covered what common names for
groups?
 Transitional
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metals, main group metals, and noble gases
Group 1- Alkali Metals
 Let’s
color code this in
 Characteristics of the Alkali Metals: They are very
reactive metals. They have only ONE electron in their
outer shell so they’re ready to lose that one electron to
other elements. They’re metals so they have
characteristics of metals too!
Common Names for other Groups Cont.
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Group 2- Alkaline Earth Metals
 Color
code and label this
 Characteristics: They’re very reactive. They also have
characteristics of metals.
Hey- What about the staircase from
yesterday?
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The stair-step line distinguishes metals from nonmetals! It’s a famous stair-step line ;)
 Let’s
label the non-metals on our table
 Notice there are multiple common named groups that
fall under “non-metals” and the same goes for the
metals.
Common Names for other Groups Cont.
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Metalloids- Boron, silicon, germanium, arsenic,
antimony, tellurium, and polonium
They are found along the stair-step line because
they’re special! They have properties of both metals
AND non-metals.
They carry an electrical charge
under special circumstances which
makes them useful in computers
and calculators.
Metalloids Cont.
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Some metalloids such as silicon, germanium, and
arsenic are semiconductors.
Semiconductors are elements that does not conduct
electricity as well as metal, but conducts slightly
better than nonmetals.
Common Named Groups Cont.
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Group 17- Halogens
 Let’s
color code!
 Characteristics: They are non-metal elements.
Compounds containing halogens are called salts. They
have 7 electrons in their outer shells.
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Rare Earth Metals
 Composed
of the Lanthanide Series and Actinide
Series
 Let’s color code!
Did we miss any?
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Yes! We forgot the few elements to the left of the
halogens.
This right side of the periodic table consists of the
non-metals.
Non-metals consist of the few elements we have
categorized or named, the halogens, and the noble
gases.
Characteristics: They are not able to conduct
electricity or heat very well, are very brittle, have
no metallic luster, and don’t reflect light.
Physical States of the Elements
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More zoomed in figure of the one on the previous
slide on pgs. 90 and 91 of your textbooks
It shows the states of the elements at room
temperature.
Notice most are solid, only two elements are liquid,
and the gaseous elements are located in the upperright hand corner (minus hydrogen).
Quiz tomorrow!
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Covers material over 3.1 and 3.2
Cannot use the periodic table you’ve color coded.
Be able to tell me key points from 3.1 (how did
Mendeleev organize his periodic table? What
change did Moseley make?)
Be able to label the common group names on a
blank periodic table (don’t have to color code, just
outline)
Be able to tell me characteristics of metals vs.
nonmetals vs. metalloids.