CHEMISTRY BOOK
CH 3: INTRODUCTION
PERIODIC TABLE
IAT-RAK –LC2/ Gr.10
Teacher: Nagham Hussam
TO THE
CH 3.1- DEVELOPMENT OF PERIODIC TABLE
THE SEARCH
FOR A
PERIODIC TABLE
By 1860, scientists had already discovered 60 elements
and determined their atomic masses.
 They noticed that some elements had similar properties.
 They gave each group of similar elements a name.
 Copper, silver, and gold were called the coinage
metals.
 Lithium, sodium, and potassium were known as
the alkali metals.
 Chlorine, bromine, and iodine were called the
halogens.
 They wanted to organize the elements into a system
that would show similarities while acknowledging
differences.

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DÖBEREINER’S TRIADS
In 1829, the German
chemist J.W. Döbereiner
classified some elements
into groups of three,
which he called triads.
 The elements in a triad
had similar chemical
properties, and their
physical properties varied
in an orderly way
according to their atomic
masses.

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DÖBEREINER’S TRIADS

Triads show a
relationship among the
densities that is true for
many triads. Density
increases with increasing
atomic mass
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MENDELEEV’S PERIODIC TABLE
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The Russian chemist, Dmitri Mendeleev, was a
professor of chemistry at the University of St.
Petersburg when he developed a periodic table of
elements.
Mendeleev later developed an improved version of
his table with the elements arranged in horizontal
rows.
This arrangement was the forerunner of today’s
periodic table.
He showed that the properties of the elements
repeat in an orderly way from row to row of the
table.
This repeated pattern is an example of periodicity
in the properties of elements.
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MENDELEEV’S PERIODIC TABLE
Periodicity is the tendency
to recur at regular intervals.
 In order to group
elements with similar
properties in the same
columns, Mendeleev had to
leave some blank spaces in
his table.
 He suggested that these
spaces represented
undiscovered elements.

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THE MODERN PERIODIC TABLE
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THE MODERN PERIODIC TABLE
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There are several places in
the modern table where an
element of higher atomic
mass comes before one of
lower atomic mass.
This is because the basis
for ordering the elements
in the table is the atomic
number, not atomic
mass.
The atomic number of an
element is equal to the
number of protons in the
nucleus.
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THE MODERN PERIODIC TABLE
Atomic number increases
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.
 In between, the
properties of the
elements change in an
orderly progression from
left to right.

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THE MODERN PERIODIC TABLE

The periodic law: The
statement that the physical
and chemical properties of
the elements repeat in a
regular pattern when they are
arranged in order of
increasing atomic number.

A group, sometimes also
called a family, consists of
the elements in a vertical
column.
Groups are numbered from
left to right.

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USING
THE PERIODIC TABLE
CH.3.2
In the modern periodic
table, elements are
arranged according to
atomic number.
 The atomic number
tells the number of
electrons it has.

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CH.3.2 USING
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

THE PERIODIC TABLE
The lineup starts with
hydrogen, which has one
electron.
Helium comes next in the
first horizontal row because
helium has two electrons.
Why does the first period
have only two elements?
Lithium has three. Only two
electrons can occupy the
first energy level in an atom.
The third electron in
lithium must be at a higher
energy level
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CH.3.2 USING


THE PERIODIC TABLE
Eight electrons are added
to Period 2 from lithium to
neon, so eight electrons
must be the number
that can occupy the
second energy level.
The third period repeats
the pattern of the second
period. Each element has
one more electron than its
neighbor to the left, and
those electrons are in the
third energy level.
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THE
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MAIN GROUPS
The main group elements are
those in Groups 1, 2, 13, 14, 15,
16, 17, and 18.
For the main group elements,
the group number is related to
the number of valence
electrons.
For elements in Groups 13, 14,
15, 16, 17, and 18, the second
digit in the group number is
equal to the number of
valence electrons.
Because elements in the same
group have the same number
of valence electrons, they have
similar properties.
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ALKALI METALS
Group 1
 Hydrogen is not a member, it is a
non-metal
 1 electron in the outer shell
 Soft and silvery metals
 Very reactive, esp. with water
 Conduct electricity
Image: http://www.learner.org/interactives/periodic/groups2.html
ALKALINE EARTH METALS
Group 2
 2 electrons in the
outer shell
 White and malleable
 Reactive, but less than
Alkali metals
 Conduct electricity
BORON FAMILY
Group 3
 3 electrons in the
outer shell
 Most are metals
 Boron is a metalloid
CARBON FAMILY
Group 4
 4 electrons in the
outer shell
 Contains metals,
metalloids, and a nonmetal Carbon (C)
NITROGEN FAMILY
Group 5
 5 electrons in the
outer shell
 Can share electrons
to form compounds
 Contains metals,
metalloids, and nonmetals
OXYGEN FAMILY
Group 6
 6 electrons in the
outer shell
 Contains metals,
metalloids, and nonmetals
 Reactive
GROUP 17
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Chlorine is in Group 17 and has
7 valence electrons.
Throughout the periodic table,
elements in the same group
have similar chemical
properties because the have
the same number of valence
electrons.
The word halogen is from the
Greek words for “salt former”.
All are non-metals.
Very reactive.
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GROUP 18
OR
(8A)

Group 18 elements have
the maximum number of
eight valence electrons in
their outermost energy
level.

Group 18 elements are
called noble gases.

The noble gases, with a
full complement of valence
electrons, are generally un
reactive.
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GROUPS
COMMON NAMES
Four groups have
commonly used names:
the Alkali Metals in
Group 1.
 the Alkaline Earth
Metals in Group 2,.
 the Halogens in Group
17.
 and the Noble gases in
Group 18.
 Transition Metals from
period 3 to 12(B Blok)
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PHYSICAL STATES
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AND
CLASSES
OF THE
ELEMENTS
The majority of the elements
are Metals. They occupy the
entire left side and center of
the periodic table.
Nonmetals occupy the
upper-right-hand corner.
Metalloids are located along
the boundary between metals
and nonmetals.
Each of these classes has
characteristic chemical and
physical properties, so by
knowing whether an element
is a metal, nonmetal, or
metalloid, you can make
predictions about its behavior.
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METALS
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With the exception of tin,
lead, and bismuth, metals
have one, two, or three
valence electrons
All metals except mercury
are solids at room
temperature; in fact, most
have extremely high melting
points.
The elements in Groups 3
through 12 of the periodic
table are called the
transition elements.
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TRANSITION ELEMENTS.
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The elements in Groups 3 through 12 of the periodic table
are called the transition elements.
All transition elements are metals.
Some period 7 transition elements are synthetic and
radioactive.
In the periodic table, two series of elements, atomic numbers
58-71 and 90-103, are placed below the main body of the
table.
The elements in these two series are known as the inner
transition elements.
Lanthanides: The first series of inner transition elements,
because they follow element number 57, lanthanum.
Because of their natural abundance on Earth is less than 0.01
percent, the lanthanides are sometimes called the rare earth
elements.
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TRANSITION ELEMENTS.
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The lanthanides consist
of the 14 elements
from number 58
(cerium, Ce) to number
71 (lutetium, Lu).
The second series of
inner transition
elements, the
actinides, have atomic
numbers ranging from
90 (thorium, Th) to 103
(lawrencium, Lr).
All of the actinides are
radioactive, and none
beyond uranium (92)
occur in nature.
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NONMETALS
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The nonmetals oxygen and
nitrogen make up 99 percent
of Earth’s atmosphere.
Most nonmetals don’t
conduct electricity, are much
poorer conductors of heat
than metals, and are brittle
when solid.
Many are gases at room
temperature; those that are
solids lack the luster of metals.
Their melting points tend to
be lower than those of metals.
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PROPERTIES
OF METAL AND NONMETAL
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METALLOIDS
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Metalloids have some
chemical and physical
properties of metals and
other properties of
nonmetals.
In the periodic table, the
metalloids lie along the
border between metals and
nonmetals.
Silicon (Si) is probably the
most well-known metalloid.
Some metalloids such as
silicon, germanium (Ge), and
arsenic (As) are
semiconductors.
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SEMICONDUCTORS
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A semiconductor: is an element that does
not conduct electricity as well as a metal, but
does conduct slightly better than a nonmetal.
The ability of a semiconductor to conduct an
electrical current can be increased by adding a
small amount of certain other elements.
Silicon’s semi conducting properties made the
computer revolution possible.
Your television, computer, handheld electronic
games, and calculator are electrical devices
that depend on silicon semiconductors.
All have miniature electrical circuits that use
silicon’s properties as a semiconductor.
The conductivity of a semiconductor can be
increased by a process known as doping.
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DEAR
STUDENTS,
The following link is the quizzes online for all the chapters
in the Chemistry book.

http://glencoe.mcgrawhill.com/sites/0078617987/student_view0/selfcheck_quizzes.html
Good luck
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