CHAPTER 3
Electronic Structure
and the Periodic Law
.
Metals, Nonmetals, and Metalloids
• Metals, Metalloids, and Nonmetals in the Periodic Table
Metals, Nonmetals, and Metalloids
• Metals, Metalloids, and Nonmetals in the Periodic Table
Properties of Metals
 Metals are good
conductors of heat and
electricity
 Metals are malleable
 Metals are ductile
 Metals have high tensile
strength
 Metals have luster
6.1
Metals, Nonmetals, and Metalloids
• Metals, Metalloids, and Nonmetals in the Periodic Table
Nonmetals
 Nonmetals are poor
conductors of heat and
electricity
 Nonmetals tend to be
brittle
 Many nonmetals are gases
at room temperature
Carbon, the graphite in “pencil
lead” is a great example of a
nonmetallic element.
Examples of Nonmetals
Sulfur, S, was once
known as “brimstone”
Graphite is not the only pure form of
carbon, C. Diamond is also carbon; the
color comes from impurities caught
within the crystal structure
Microspheres of
phosphorus, P, a
reactive nonmetal
6.1
Metals, Nonmetals, and Metalloids
• Metals, Metalloids, and Nonmetals in the Periodic Table
Properties of Metalloids
 They have properties of
both metals and nonmetals.
Metalloids are more brittle
than metals, less brittle than
most nonmetallic solids
 Metalloids are
semiconductors of electricity
 Some metalloids possess
metallic luster
Polonium is NOT a metalloid
Silicon, Si – A Metalloid
 Silicon has metallic luster
 Silicon is brittle like a
nonmetal
 Silicon is a semiconductor of
electricity
Other metalloids include:
 Boron, B
 Germanium, Ge
 Arsenic, As
 Antimony, Sb
 Tellurium, Te
3.1 PERIODIC LAW
• This is a statement about the behavior of the elements when they
are arranged in a specific order.
• PERIODIC LAW:
Elements with similar chemical properties
occur at regular (periodic) intervals when
the elements are arranged in order of
increasing atomic numbers.
PERIODIC TABLE
• A periodic table is a tabular arrangement of the elements based on
the periodic law.
• In a modern periodic table, elements with similar chemical
properties are found in vertical columns called groups or families.
18 groups/families
7
periods
PERIODIC TABLE GROUP OR FAMILY
• A group or family is a vertical column of elements that
have similar chemical properties.
• Each family has a specific name to differentiate it from the other
families in the periodic table.
• Elements in each family react differently with other elements.
• The U.S. system uses a Roman numeral and a letter (either
A or B) at the top of the column. The IUPAC (but not
universally-used) system uses only a number from 1 to 18.
Alkali Metals
All alkali metals have 1
valence electron
Alkali metals are NEVER
found pure in nature; they are
too reactive
Reactivity of these elements
increases down the group
Hydrogen is not a member, it
is a non-metal
Potassium, K
reacts with water
and must be
stored in
kerosene
Alkaline Earth Metals
• All alkaline earth metals have 2 valence
electrons
• Alkaline earth metals are less reactive than
alkali metals
• Alkaline earth metals are not found pure in
nature; they are too reactive
• The word “alkaline” means “basic”
• common bases include salts of the metals
• Ca(OH)2
• Mg(OH)2
Halogens
 Halogens all have 7 valence
electrons
 Halogens are never found pure in
nature; they are too reactive
 Halogens in their pure form are
diatomic molecules (F2, Cl2, Br2, and I2)
All are non-metals
Very reactive are often bonded with
elements from Group 1

Chlorine is a yellow-green
poisonous gas
Noble Gases
Noble gases are ONLY found pure in
nature – they are chemically unreactive
Exist as gases
Non-metals
8 electrons in the outer shell = Full
Helium (He) has only 2 electrons in
the outer shell = Full
Colorless, odorless and unreactive; they
were among the last of the natural
elements to be discovered
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
non-metal Carbon
(C)
NITROGEN FAMILY
Group 5
• 5 electrons in the
outer shell
• Can share electrons
to form compounds
• Contains metals,
metalloids, and
non-metals
OXYGEN FAMILY
Group 6
• 6 electrons in the
outer shell
• Contains metals,
metalloids, and
non-metals
• Reactive
TRANSITION METALS
Groups in the middle
 Good conductors of
heat and electricity.
 Some are used for
jewelry.
 The transition metals
are able to put up to
32 electrons in their
second to last shell.
 Can bond with many
elements in a variety
of shapes.
Rare Earth Metals
• Some are
Radioactive
• The rare
earths are
silver, silverywhite, or gray
metals.
• Conduct
electricity
PERIODIC TABLE PERIOD
• A period is a horizontal row of elements arranged according to
increasing atomic numbers.
• Periods are numbered from top to bottom of the periodic table.
MODERN PERIODIC TABLE
• Elements 58-71 and 90-103 are not placed in their correct periods,
but are located below the main table.
GROUP & PERIOD IDENTIFICATION
• ELEMENTS AND THE PERIODIC TABLE
• Each element belongs to a group and period of the periodic
table.
• EXAMPLES OF GROUP AND PERIOD LOCATION FOR
ELEMENTS
• Calcium, Ca, element 20: group II A (2), period 4
• Silver, Ag, element 47: group I B (11), period 5
• Sulfur, S, element 16: group VI A (16), period 3
3.2 BOHR THEORY
• Bohr proposed that the
electron in a hydrogen
atom moved in any one of
a series of circular orbits
around the nucleus.
• The electron could change
orbits only by absorbing or
releasing energy.
• This model was replaced
by a revised model of
atomic structure in 1926.