START
LESSON
TEACHER'S
NOTES
Teacher's Notes
Subject: Chemistry
Topic: The periodic table
Grades: 7-9
Prior Knowledge: The atomic structure of elements.
Lesson Objectives
By the end of this lesson students should understand:
·electron shells
·valence shells
·how atomic numbers are derived by the number of protons in the
atomic structure
·how the periodic table is organized by atomic
number, number of
electron shells (rows), and number of protons in the valence shell
(columns)
·how the periodic table is organized into different
families of
properties
Lesson Notes
Dmitri Mendeleev published the first periodic table in 1869. This
lesson is a brief introduction to the periodic table.
Major lesson points:
·The atomic number is based on the number of protons in an
element's atomic structure.
·In a natural state, an element has an identical number of
neutrons. Neutrons are not discussed
here, however.
protons, electrons, and
·Elements are often arranged in columns according to the number
of electrons in the valence or outer shell of an atom.
·Transition metals, lanthanoids (or lanthanides) and actinoids (or
actinides) look at the electrons orbiting beneath the outer
to understand their atomic structure.
shell to subshells
The lesson concludes with an assessment of the students learning of the lesson
concepts and objectives.
The periodic table is designed to classify the elements.
Let’s start with Hydrogen and Helium.
Touch the sun, then drag to the terms to the correct line, then drag
hydrogen to box 1 and helium to box 2.
Sorting four more elements.
Pull the tabs, read the descriptions, then move each atom to its
correct place.
Hydrogen
has one proton, therefore, its atomic
H
number is 1.
He
Lithium has 3 protons. 2 electrons reside in its inner
Li with 1 on the valence shell. Move lithium to it's
shell
correct place.
Ne
Sodium has 11 protons. 2 electrons are in the inner shell, 8 in the 2 shell,
Na just 1 in the valence shell. Move sodium to its correct place.
and
nd
Ar
Placing more elements on the periodic table.
Columns 1-2 and 13-18.
Touch each element to enlarge. Study their
valence shells.
Placing more elements on the periodic table.
Columns 1-2 and 13-18.
Touch the elements on the right to reveal their atomic structure. Pull
and read each tab.
Si
Selenium has 34 protons. 2 electrons are in the inner shell, 8 in the 2nd shell,
Se
18 in the 3rd shell, and 6 in the valence shell. Move selenium to its correct place
on the chart.
Cl
Gallium has 31 protons. 2 electrons are in the inner shell,
Ga
8 in the 2nd shell, 18 in the 3rd shell, and 3 in the valence shell. Move gallium to
its correct place on the chart.
Uup
Calcium has 20 protons. 2 electrons are in the inner shell,
8Cain the 2nd shell, 8 in the 3rd shell and 2 in the valence shell. Move calcium to
its correct place on the chart.
Placing more elements on the periodic table.
Columns 1-2 and 13-18.
Placing more elements on the periodic table.
Columns 3-12.
Study each atom and their valence shells.
Move them to the correct box on the chart.
The elements in these sections have either 0, 1, or 2
electrons in their valence shells. This makes it difficult to
find the correct column for each element. In an element's standard form, there is one
electron for each proton. Add the column of electrons to determine the number of
protons and atomic number for each element.
Elements have different properties influenced
by their molecular structure.
Touch each colored area to learn about its
unique properties.
Click here to classify columns
13-16 in another way.
Halogens
Oyxgen family
Actinoids
Nitrogen family
Lanthanoids
Carbon family
Transitional
Metals
Boron family
Alkali metals
Within column 3, rows 6 and 7 have many elements that
are very similar in properties. In order to conserve space, two additional rows
have been created at the bottom, representing elements 57-71 (lanthanoids)
and 89-103 (actinoids).
Noble Gases
Alkaline Earth metals
Version #1-(for Boron, Carbon, Nitrogen, Oxygen
families)
Alkali metals
Alkali metals: These elements have 1 electron in the valence shell.
They react easily with other elements. These are not found in
elemental form in nature. They are lighter and softer than alkalines.
Alkaline Earth Metals
Alkaline Earth Metals: These elements have 2 electrons in the
valence shell. They react easily with other elements. They form ionic
salts with halogens. They are heavier and harder than alkali metals.
Transitional Metals
Transition Metals have properties that reflect their unique electron
structure. Note that the valence shell holds 0, 1, or 2 electrons but
the inner shell has a differing count of electrons. Transition Metals are
very hard. They have high melting and boiling points. They conduct
electricity.
Boron Family
Boron Family: Elements in this family contain 3 electrons in the
valence shell. These elements form stable bonds with other
elements.
Carbon Family
Carbon Family: Elements in this family contain 4 electrons in the
valence shell. These elements form stable bonds with other
elements.
Nitrogen Family
Nitrogen Family (also known as pnictogen):
Elements in this family have 5 electrons in the valence shell.
Oyxgen Family
Oxygen Family (also known as chalcogen):
Elements in this family have 6 electrons in the valence shell.
Halogens
Halogens: These elements have 7 electrons in their valence shell
and are highly reactive.
They can be harmful or lethal to biological organisms and some are
used as disinfectants.
Noble Gases
Noble gases have a full valence shell and are very
stable and nonreactive with other elements. Electric
currents cause these gases to light up. Noble gases
are used as refrigerants because of their low boiling
and melting points.
Lanthanoids
Lanthanoids: The first additional row, elements 57-71, are named
after the first element in this group, lanthanum. Because lanthanoids
deflect ultraviolet and infrared radiation, they are used in sunglasses.
They are also used in catalytic converters and as catalysts to refine
petroleum.
Actinoids
Actinoids: The second additional row, elements 89-103, are named after
the first element in this group, actinium. All actinoids are radioactive.
Since most actinoids are difficult to find naturally, scientists synthesize
them in laboratories. Supernovae, nuclear reactors and nuclear
explosions also create actinoids, which then decay.
Elements have different properties influenced
by their molecular structure.
Touch each colored area to learn about its
unique properties.
Click here to classify columns
13-16 in another way.
Lanthanoids
Actinoids
Noble Gases
Transitional
Metals
Halogens
Alkali metals
Alkaline Earth metals
Version #2-(for Nonmetal, Metalloid, Poor)
Alkali metals
Alkali metals: These elements have 1 electron in the valence shell.
They react easily with other elements. These are not found in
elemental form in nature. They are lighter and softer than alkalines.
Alkaline Earth metals
Alkaline Earth Metals: These elements have 2 electrons in the
valence shell. They react easily with other elements. They form ionic
salts with halogens. They are heavier and harder than alkali metals.
Transitional Metals
Transition Metals: Have properties that reflect their unique electron
structure. Note that the valence shell holds 0, 1, or 2 electrons but
the inner shell has a differing count of electrons. Transition metals are
very hard. They have high melting and boiling points. They conduct
electricity.
Poor
Poor (or Post Transition): These metals are softer
with lower melting and boiling points than transition metals.
Metaloids
Metalloids: These elements can react as an acid or base. They often
behave as semiconductors.
Nonmetals
Non-metals: These elements conduct heat and electricity poorly, they
have significantly lower melting and boiling points, and lower densities.
Hydrogen is classified as a non-metal.
Halogens
Halogens: Elements have 7 electrons in their valence
shell and are highly reactive. They can be harmful or
lethal to biological organisms and some are used as disinfectants.
Noble Gases
Noble gases have a full valence shell and are very
stable and nonreactive with other elements. Electric
currents cause these gases to light up. Noble gases have low boiling and
melting points and are used as refrigerants.
Lanthanoids
Lanthanoids: The first additional row, elements 57-71, named after the
first element in this group, lanthanum. Because lanthanoids deflect
ultraviolet and infrared radiation they are used in sunglasses. They are
also used in catalytic converters and as catalysts to refine petroleum.
Actinoids
Actinoids: The second additional row, elements 89-103, named after
the first element in this group, actinium.
All actinoids are radioactive. Since most actinoids are difficult to find
naturally, scientists synthesize them in laboratories. Supernovae,
nuclear reactors and nuclear explosions also create actinoids, which
then decay.
1
The atomic number is ___________.
A
B
C
D
the number of neutrons in an atom
the weight of an atom
the total number of protons, neutrons, and electrons in an atom
the number of protons in an atom
In its standard form, an element will have twice as many
electrons as protons.
2
A
B
True
False
3
Noble gases are nonreactive.
A
B
True
False
4
All elements are found naturally on Earth.
A
B
True
False
Elements are not found outside of Earth's atmosphere.
5
A
B
True
False
6
What is a valence shell?
A
B
C
D
The outer shell of an atom.
The proton shell of an atom.
An inner shell of an atom.
A middle shell of an atom.
Place the have
following
words
in a column
Elements
different
properties
influenced
beneath
the two images:
by
their molecular
structure.
Atomic #1
Nonreactive
Hydrogen
Helium
Reactive
Atomic #2
Answer have different properties influenced
Elements
by their molecular structure.
Atomic #1
Atomic #2
Hydrogen
Helium
Reactive
Nonreactive
The periodic table primarily sorts elements according to which
criteria:
7
A
gases, liquids, solids.
B
valence shell electrons.
C
natural and synthetic.
D
metals and nonmetals.
Which of the following represents this atom on the periodic
table?
8
A
Gold
B
Phosphorus
C
Iron
D
Copper