Transcript Periodic Table

Ch. 5 - The Periodic Table
I. History of the Periodic Table
Mendeleev
Mosely
Periodic Law
A. Dmitri Mendeleev
 Dmitri Mendeleev (1869, Russian)
• Organized elements by
increasing atomic mass.
• Predicted the existence of
undiscovered elements.
B. Henry Mosely
 Henry Mosely (1913, British)
• Organized elements by
increasing atomic number.
• Fixed problems in Mendeleev’s
arrangement.
C. Periodic Law
Properties of elements repeat
in a predictable way when
atomic numbers are used to
arrange elements into groups.
Key Concept
How is the modern periodic
table organized?
In the modern periodic table,
elements are arranged by
increasing number of protons.
Ch. 5 - The Periodic Table
II. Organization
Metallic Character
Rows & Columns
Table Sections
A. Metallic Character
1
2
3
4
5
6
7
 Metals
 Nonmetals
 Metalloids
A. Metallic Character
The majority of
the elements on
the periodic table
are classified as
metals.
• Metals are elements that
are good conductors of
electric current and heat.
• Except for mercury,
metals are solid at room
temperature.
• Most metals are solids.
• Many metals are ductile;
that is, they can be bent
or drawn in to wires. .
A. Metallic Character
Nonmetals
generally have
properties
opposite to
those of metals.
• Nonmetals are elements
that are poor conductors of
heat and electric current.
• Nonmetals have low boiling
points – many nonmetals
are gases at room
temperature.
• Nonmetals that are solids at
room temperature tend to be
brittle. If they are hit with a
hammer, they shatter or
crumble.
A. Metallic Character
•
Metalloid
elements are
located on the
•
periodic table
between metals
and nonmetals.
Metalloids are elements with
properties that fall between
those of metals and
nonmetals.
For example, a metalloid’s
ability to conduct electric
current varies with
temperature. Silicon (Si) and
Germanium (Ge) are good
insulators at low temperatures
and good conductors at high
temperatures.
B. Rows and Columns
 Representative Elements
 Transition Metals
1
2
3
4
5
6
7
B. Rows and Columns
1
2
3
4
5
6
7
 Group (Family)
 Period
B. Rows and Columns
Each column in the periodic table
is called a Group or Family.
• The elements in a group have the
same number of valence electrons,
so members of the same group in
the periodic table have similar
chemical properties.
• This pattern of repeating properties
is the periodic law.
B. Rows and Columns
Each column in the periodic table of elements is a
Group.
1 valence electron.
 Elements in group 1 have ___
2 valence electrons.
 Elements in group 2 have ___
3 valence electrons.
 Elements in group 13 have ___
4 valence electrons.
 Elements in group 14 have ___
5 valence electrons.
 Elements in group 15 have ___
6 valence electrons.
 Elements in group 16 have ___
7 valence electrons.
 Elements in group 17 have ___
8 valence electrons.
 Elements in group 18 have ___
B. Rows and Columns
Each row in the table of elements is a Period.
•
•
•
•
•
•
•
1 have one energy level.
Elements in period __
2 have two energy levels.
Elements in period __
3 have three energy levels.
Elements in period __
4 have four energy levels.
Elements in period __
5 have five energy levels.
Elements in period __
6 have six energy levels.
Elements in period __
7 have seven energy levels.
Elements in period __
Horizontally Into Periods
The Periodic Table
III. Periodic Trends
Terms
Dot Diagrams
Review
There are four pieces of information for each
element.
1. _______________
2. _______________
3. _______________
4. ______________
A. Terms
 Periodic Law
• Properties of elements repeat
periodically when the elements
are arranged by increasing
atomic number.
A. Terms
 Valence Electrons
• e- in the outermost energy level
A. Terms
 Group # = # of valence e- (except He)
• Families have similar chemical characteristics .
 Period # = # of energy levels
1A
1
2
3
4
5
6
7
8A
2A
3A 4A 5A 6A 7A
B. Dot Diagrams
 Dots represent the valence e-.
 Ex.: Sodium
 Ex.: Chlorine