Chapter Menu
Section 3.1
Development of the
Periodic Table
Section 3.2
Using the Periodic Table
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Development of the Periodic Table
• Outline the steps in the historical development
of the periodic table.
• Predict similarities in properties of the
elements by using the periodic table.
Development of the Periodic Table
electron cloud: space around the nucleus of
an atom where the atom’s electrons are found
Development of the Periodic Table
periodicity
periodic law
The periodic table evolved over time as
scientists discovered more useful ways
to compare and organize the elements.
The Search for a Periodic Table
• Early scientists needed a system that would
show similarities and differences between
individual and groups of elements.
• J.W. Döbereiner classified some elements
that had similar chemical properties into
triads, organizing them according to their
atomic mass.
The Search for a Periodic Table (cont.)
The Search for a Periodic Table (cont.)
• Dmitri Mendeleev’s research revealed that
the chemical and physical properties of the
elements repeated in an orderly way when
he organized the elements according to
increasing atomic mass.
• Density, melting point, and boiling point all
increase as atomic mass increases.
The Search for a Periodic Table (cont.)
The Search for a Periodic Table (cont.)
• By applying his theory of periodicity, or
the tendency to recur at regular intervals,
Mendeleev was able to predict properties
of elements that had not yet been
discovered.
The Search for a Periodic Table (cont.)
The Search for a Periodic Table (cont.)
• Henry Mosley proposed rearranging the
elements according to their atomic number,
which resulted in the structure of the
modern periodic table.
The Search for a Periodic Table (cont.)
The Modern Periodic Table
• Each block of the modern periodic table
shows the element’s name, symbol, atomic
number, and atomic mass.
• At present, elements up to atomic number
118 have been discovered or synthesized.
• Atomic number increases by one as you
move from element to element across a row.
The Modern Periodic Table (cont.)
• With the exception of the first row, each
row begins with a metal and ends with a
noble gas.
• The idea that the physical and chemical
properties of the elements repeat in a regular
pattern when they are arranged in order of
increasing atomic number is known as the
periodic law.
Section Assessment
The return of the full moon every 28 days
is an example of ___.
A. phases
B. periodicity
C. frequency
D. periodic law
Section Assessment
The most unreactive elements are found
in which group?
A. 1
B. 2
C. 17
D. 18
Using the Periodic Table
• Relate an element’s valence electron structure
to its position in the periodic table.
• Use the periodic table to classify an element
as a metal, nonmetal, or metalloid.
• Compare the properties of metals, nonmetals,
and metalloids.
Using the Periodic Table
periodicity: the tendency to recur at regular
intervals
Using the Periodic Table
period
lanthanide
group
actinide
noble gas
nonmetal
metal
metalloid
transition element
semiconductor
Elements are organized in the periodic
table according to their electron
configurations.
Relationship of the Periodic Table to
Atomic Structure
• Elements are organized in the periodic
table according to their electron
configurations.
Periods and Groups
• A period is a horizontal row on the periodic
table.
• A group, or family, consists of elements in a
vertical column of the periodic table.
Periods and Groups (cont.)
• Group 18 elements, which have the
maximum number of eight valence
electrons and are generally unreactive, are
known as the noble gases.
• The period number of an element is the same
as the number of its outermost energy level.
Periods and Groups (cont.)
• The number of valence electrons changes
from one to eight as you move from left to
right across a period; when you get to
group 18, the
pattern repeats.
Periods and Groups (cont.)
• Because elements in the same group have
the same number of valence electrons,
they have similar properties.
Periods and Groups (cont.)
• Common names for some groups
– alkali metals in group 1
– alkaline earth metals in group 2
– halogens in group 17
– noble gases in group 18
Physical States and Classes
of the Elements
• Most elements are solid at room
temperature and normal atmospheric
pressure.
• Synthetic elements are not found in nature
but are produced artificially in particle
accelerators.
Physical States and Classes
of the Elements (cont.)
• Elements are classified as metals,
metalloids, or nonmetals on the basis of
their physical and chemical properties.
Physical States and Classes
of the Elements (cont.)
• Metals are elements that have luster,
conduct heat and electricity, and usually
bend without breaking.
– The majority of elements are metals.
– Most metals are solid at room temperature
and have extremely high melting points.
– With the exception of tin, lead, and
bismuth, metals have one, two, or three
valence electrons.
Physical States and Classes
of the Elements (cont.)
• The metals in groups 3 through 12 of the
periodic table are called the transition
elements.
• The unpredictable behavior and properties of
the transition metals is due to the more
complicated atomic structure of these
elements.
Physical States and Classes
of the Elements (cont.)
• The transition elements are divided into
transition metals and inner transition metals.
• The two sets of inner transition metals are
called the lanthanide series and actinide
series and are located
at the bottom of the
periodic table.
Physical States and Classes
of the Elements (cont.)
• Nonmetals are elements that are generally
gases or brittle, dull-looking solids, and poor
conductors of heat and electricity.
Physical States and Classes
of the Elements (cont.)
• Metalloids have physical and chemical
properties of both metals and nonmetals, such
as silicon and germanium.
• Some metalloids are semiconductors, or an
element that does not conduct electricity as
well as a metal but does conduct slightly
better than a nonmetal.
Physical States and Classes
of the Elements (cont.)
• When undergoing chemical reactions, metals
tend to lose valence electrons, whereas
nonmetals tend to share electrons or gain
electrons from other atoms.
Semiconductors and Their Uses
• Most metals conduct an electric current
because their valence electrons are not
held tightly by the positive nucleus and are
free to move.
Semiconductors and Their Uses (cont.)
• The electrical conductivity of a semiconductor
such as silicon can be increased by a process
known as doping—the addition of a small
amount of another element to a crystal of a
semiconductor.
– n-type semiconductor
– p-type semiconductor
Semiconductors and Their Uses (cont.)
Semiconductors and Their Uses (cont.)
• Many semiconductors are made by
combining n- and p-type semiconductors to
form a diode.
• Transistors, diodes, and other
semiconductors are incorporated into thin
slices of silicon to form integrated circuits and
are widely used in the development of
technology.
Section Assessment
An element with a full octet has how many
valence electrons?
A. two
B. six
C. eight
D. ten
Section Assessment
The actinide series is part of the:
A. s-block elements
B. inner transition metals
C. nonmetals
D. alkali metals
Chemistry Online
Study Guide
Chapter Assessment
Standardized Test Practice
Image Bank
Concepts in Motion
Key Concepts
• In his periodic table, Mendeleev organized the
elements according to increasing atomic mass and
placed elements with similar properties into groups.
• The modern periodic law states that the physical and
chemical properties of the elements repeat in a
regular pattern when they are arranged in order of
increasing atomic number.
Key Concepts
• Atomic structure and the number of valence electrons
can be related to an element’s position on the periodic
table.
• Elements are classified as metals, nonmetals, or
metalloids.
• The number of valence electrons and how tightly they
are held determine the chemical properties of an
element.
• The conductivity of semiconductors can be increased by
adding small amounts of other elements.
Which chemist used triads to organize
elements?
A. Döbereiner
B. Mendeleev
C. Moseley
D. Curie
Elements are organized in the periodic
table according to their ___
configurations.
A. electron
B. proton
C. neutron
D. atomic
What is a row of elements on the periodic
table called?
A. octave
B. period
C. group
D. transition
At room temperature and in normal
atmospheric pressure, most elements
are ___.
A. gases
B. liquids
C. solids
By which method are synthetic elements
created?
A. nuclear reactions
B. splitting electrons
C. chemical reactions
D. splitting neutrons
The majority of elements are ___.
A. synthetic
B. metalloids
C. nonmetals
D. metals
Which element is a transition element?
A. nickel
B. zinc
C. tin
D. lead
Which elements are sometimes called the
rare earth elements?
A. actinides
B. lanthanides
C. noble gases
D. metalloids
Which group of elements are the least
reactive?
A. alkali metals
B. inner transition metals
C. halogens
D. noble gases
What is silicon an example of?
A. metal
B. nonmetal
C. metalloid
D. inner transition metal
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Table 3.5
Properties of Metals
and Nonmetals
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