Transcript The Periodic Table

Chapter 5
The Periodic Table
Pages 124-155
Pre-section 1
Reading the Periodic Table
Before we go into the table’s history, let’s learn
how to read it.
The Periodic Table
All known elements are organized into an
easy to use reference tool called
The Periodic Table
The Periodic Table

Similar properties occur in a regular
patterns throughout the table

The periodic table helps us determine
electron arrangement and helps us figure
out how certain elements will react with
one another
Periods

Periods – Horizontal Rows [Like number of
energy levels]
Groups or Families

Groups or Families – Vertical Columns
[Like number of valence electrons]
How to Read Those Boxes
[Review]
Number of Protons or
Electrons
13
Al
Number of Protons +
Neutrons
Atomic Number
Symbol
Aluminum
Element Name
26.981538
Average atomic Mass
Mass is measured in Atomic Mass Units [AMUs]
An AMU is equal to the mass of one proton or
neutron.
Families of Elements
Based on what you know about atoms and
the periodic table, how are elements
classified?
Families of Elements
Elements are classified into three main
groups:
1. Metals
2. Non-metals
3. Metalloids or Semi-conductors
Metals
Good Conductors, Shiny, Dense, Malleable
Alkali Metals



Most reactive family of metals
Located in group one (Except H)
Lose one electron when ionized to have
1+ charge
Alkaline – Earth Metals
Relatively reactive (less than Alkali Metals)
 Located in group two
 Lose two electrons when ionized to have
2+ charge

Transition Metals
Much less reactive metals
 Can gain or lose electrons to form
‘Cations’ with a positive charge or ‘Anions’
with a negative charge
 Can form 1+, 2+, etc…

Other Metals
Many of the same characteristics of
previously noted metals
Totally
Looks
Like
Idaho
Metalloids
Properties of metals & non-metals
 Some carry electrical charges under
special conditions

Boron
Silicon
Germanium
Arsenic
Antimony
Tellurium
Non-Metals
Poor conductors, lack luster, shatter
The most plentiful on Earth are O, C, H, & N
Halogens
Most reactive non-metals
 Known as the “Salt Makers”
 Lack one valence electron (gain 1 e-)

Nobel Gases
Inert Gases – Do not react with other
elements
 Full / Stable outer energy level (no charge)

Section 1
Organizing the Elements
Pages 126-129
The Search for Order

Until 1750, scientists had only identified
17 elements. Other elements were still
around but they had not been identified
because the technology was not available.

In 1789, French Chemist Antoine Lavoisier
grouped the known elements into
categories he called metals, nonmetals,
gases, and earths.
The Search for Order

80 years later, a Russian teacher named
Dmitri Mendeleev organized the earliest
periodic table.
Mendeleev’s Periodic Table

Mendeleev arranged the elements into
rows in order of increasing mass so that
elements with similar properties were in
the same column.

A periodic table is an arrangement of
elements in columns based on a set of
properties that repeat from row to row.
Mendeleev’s Periodic Table

There were some gaps in the table but he
was sure they would be filled later by other
elements that had not yet been
discovered.

The close match between Mendeleev’s
predictions and the actual properties of
new elements showed how
useful his periodic table could be.
Well…
Technically, section one stops here but we’re
just going to roll it into section two…
Section 2
The Modern Periodic Table
Pages 130-138
The Periodic Law

In the modern periodic table, elements are
arranged by increasing atomic number
[number of protons].

Properties of elements repeat in a
predictable way when atomic numbers are
used to arrange elements into groups.
This pattern is called the periodic law.
The Periodic Law

Each horizontal row is a period.

Each vertical column is a group.
Atomic Mass

Atomic mass is a value that depends on
the distribution of an element’s isotopes in
nature and the masses of those isotopes.

An atomic mass unit is defined as one
twelfth the mass of a carbon-12 atom.
Classes of Elements

Elements are classified as metals, nonmetals,
and metalloids.

Metals are good conductors, lustrous, dense,
malleable, ductile, and [except for mercury] a
solid at room temperature.

Transition metals were the first metals identified
and are often noted for their distinctive colors
when mixed with glass.
Metals
Transition Metal Colors
[In Glass]
Mn
Fe
Ni
Cr
Cu
Co
Au
U
Nonmetals
Poor conductors, lack luster, and shatter
 Most plentiful on Earth: C, H, O, & N

H
O
N
Metalloids

Elements with properties that fall between
those of metals and nonmetals. They are
good conductors at certain temperatures.
Variation Across a Period

Across a period from left to right, the
elements become less metallic and more
nonmetallic in their properties.
Collaborate and listen.
Hammertime…
Section 3
Representative Groups
Pages 139-145
Valence Electrons

A valence electron is an electron that is in
the highest occupied energy level of an
atom.

Elements in a group have similar
properties because they have the same
number of valence electrons.
The Alkali Metals

The elements in Group 1A are called
alkali metals.

The reactivity of alkali metals
increases from the top of Group 1A to
the bottom
The Alkali Metals
S
k
i
p
t
o
1
m
i
n
Alkaline Earth Metals

The elements in Group 2A are called
alkaline earth metals.

Differences in reactivity among the
alkaline earth metals are shown by
the ways they react with water.
Alkaline Earth Metals
The Boron Family
The elements in Group 3A are called
Boron Family.
 Increases the strength of glass.

The Boron Family
The Carbon Family
The elements in Group 4A are called
Carbon Family.
 Humans contain mostly carbon.

Group
4A
The Nitrogen Family
The elements in Group 5A are called
the Nitrogen Family.
 Often used in fertilizers.

The Nitrogen Family
The Oxygen Family

The elements in Group 6A are called
the Oxygen Family.
The Halogens

The elements in Group 7A are called
Halogens.
The Halogens
The Nobel Gases

The elements in Group 8A are
called Nobel Gases.

The noble gases are colorless,
odorless, and extremely
nonreactive.
Elemental Friends and Foes

Hydrogen accounts for 60% of your body
mass. Found in water.

Vanadium can control blood sugar levels.
Found in peppercorns.

Iron is in hemoglobin and helps transport
oxygen through the body.
Elemental Friends and Foes

Lead, found in paint, can lead to organ
damage and learning difficulties.

Arsenic was once used to protect crops
and preserve wood.

Too much sodium can lead to high blood
pressure.