Yakima WATERS Mini Lesson
Periodic Trends
Targets and Assessment
WA Science Standards Addressed:
9-11
PS2B
Atoms of the same element have the same
number of protons. The number and
arrangement of electrons determines how the
atom interacts with other atoms to form
molecules and ionic crystals.
When elements are listed in order according to
the number of protons, repeating patterns of
physical and chemical properties identify
families of elements with similar properties.
This Periodic Table is a consequence of the
repeating pattern of outermost electrons.
Assessments:
 The student worksheet
Lesson Parameters
Content Area: Chemistry
Overview: In this lesson student will learn about the
organization of the periodic table and the trends of the
periodic table
Grade Level: 11th&12th grader
9-11
PS2C
Suggested Time: Two 50 minute class periods
Special Materials:

Learning Outcomes:
Knowledge: Upon completion of this lesson students should understand the periodic tables format is a
direct result of the periodic nature of elemental properties.
Skill: students should be able to use the periodic table to determine various atomic properties such as
atomic radius, ionic radius, effective nuclear charge, electron affinity, electronegativity, atomic mass
and electron configuration using the periodic table. Students should also be able to describe the
periodic trends.
Science Concept Background:
The periodic table is the most useful tool for chemists as it has organized elements in way that aids in
remembering chemical and physical properties of elements. The structure of the periodic table is a
direct result of the periodic nature of elemental properties, which is very important for chemistry
students to understand. Elements in the same column have the same number of valance electrons;
they often have the same charge and are in the same state of matter. Elements in the same column
often are involved in similar chemical process, have similar electron configurations, have similar
electron affinity and ionization energies. The periodicity of chemical and physical properties can easily
be determined knowing a few periodic trends such as effective nuclear charge, atomic radius, electron
affinity, electronegativity and electron configuration.
Materials:
- One periodic table (the one attached to this document) per students cut into individual elements.
- The student worksheet entitled Designing the Periodic table (see attached documents), one per
students.
- The periodic trend power point.
Procedure:
1) Give students the designing the periodic table work sheet and a periodic table (cut into individual
elements).
2) Give student the legend (below) for the periodic table.
3) Let students work through Part 1, when everyone has finished discus as a class the how they
organized their periodic tables be sure to compare different tables and what patterns they see and
how those patterns differ among the various periodic tables.
4) Let the students work through Part 2, when everyone is done have another class discussion. Discus
how they organized their periodic tables be sure to compare different tables and what patterns
they see and how those patterns differ among the various periodic tables.
5) In Part 3 student pairs need to need to organize two periodic tables, this means you’ll need a few
more periodic tables. One should make a periodic table in order of atomic number; the other
students should make a periodic table in order of atomic mass. Have the pairs of student observe
and discus the difference between the two periodic table.
6) When student have completed parts 1-3 give a short lecture on the set up of the periodic table and
periodic trends. Then have students’ complete part 4.
Extension(s):
Trends of Groups 1A, 2A, 6A, 7A &9A power point and worksheet.
Teaching Tips:
Supplements:
Student worksheet entitled Designing the Periodic Table (attached)
Periodic Table (separate document)
Periodic Trends PowerPoint (separate document)
Author: Sara Rosario, Yakima WATERS Project, CWU, Fall 2010
Name:
Date:
Period:
Designing the Periodic Table
Part 1: Pick one chemical or physical property (Ex. Atomic radius) order your elements using that property.
When you are done answer the following questions and sketch a diagram of your periodic table in the space
provided bellow.
Sketch of periodic table:
1) Which property have you chosen to organize your periodic table with?
2) Look at your table carefully. Are you noticing any trends (repeating pattern of atom properties)
develop? If so please describe what the trends are present and how frequently each occurs.
Part 2: Now it’s time to add a second level of organization. Pick at least two properties that have obvious
repeating patterns or trends and reorganize your periodic table so that those elements are clustered together.
When you are done answer the following questions and sketch a diagram of your periodic table in the space
provided bellow.
Sketch of periodic table:
1) Which properties have you chosen to reorganize your periodic table with?
2) Look at your table carefully. Are you noticing any other trends (repeating pattern of atom
properties) develop? If so please describe what the trends are present and how frequently each
occurs.
Part 3: Find a partner, one partner should organize a periodic table by ordering elements in increasing atomic
number then grouping element with similar chemical and physical properties. The other partner should
organize their periodic table by ordering elements in increasing atomic mass, then by grouping elements with
similar properties. When you are done compare and contrast the two periodic tables and answer the
questions below.
1) How does the order of elements in periodic table organized by increasing atomic mass differ from
the periodic table organized by increasing atomic number?
2) Propose an explanation for why the arrangement of element in the periodic table organized
according to atomic mass.
Part 4: Answer the following Question
1) As we move across the rows of the periodic table atomic weight increases but atomic radius
decreases. Why are these two trends contradictory?
2) Draw a simple sketch of the periodic table; now draw a straight arrow from the elements with the
smallest atomic radii to the elements with the largest atomic radii. Hint; exclude hydrogen and
Helium. How do atomic radii change as we move from left to right across each period and when we
move from top to bottom across each group?
3) Draw a simple sketch of the periodic table; now draw a straight arrow from the elements with the
smallest ionization energy to the elements with the largest. How do ionization energies change as
we move from right to left and bottom to top of the periodic table?
4) Using the blank periodic table below, label element as metal, metalloids or non-metals.
5) Using the blank periodic table below, label groups 1A, 2A, 5A, 6A and 7A with the appropriate
charges.
6) Explain effective nuclear charge. How does effective nuclear charge change as you move across
rows and down columns of the periodic table
7) Using the blank periodic table below, label groups and rows of elements with the correct electron
configurations.
8) Draw a simple sketch of the periodic table; now draw a straight arrow from the elements with the
smallest electron affinity to the elements with the largest electron affinity. Hint; exclude hydrogen
and Helium. How does electron affinity change as we move from left to right across each period
and when we move from top to bottom across each group?
9) Draw a simple sketch of the periodic table; now draw a straight arrow from the elements with the
smallest ionic radii to the elements with the largest ionic radii. . How does ionic radius changes as
we move from left to right across each period and when we move from top to bottom across each
group?
10) Draw a simple sketch of the periodic table; now draw a straight arrow from the elements with the
smallest electronegativity to the elements with the largest electronegativity. How does
electronegativity changes as we move from left to right across each period and when we move
from top to bottom across each group?
11) Compare and contrast Electron affinity and electronegativity.
12) What two factors have the greatest affect the properties of elements? And propose an explanation
why?
Name:
Date:
Period:
1)
2)
3)
4)
5)
Group trends worksheet
The alkali metals are in group 1A of the periodic table, what characteristics properties do these
elements share? How do atomic radius, ionization energy and reactivity change as you move down
this group?
What characteristic properties do the halogens (group 7A) share? How does atomic radius,
ionization energy and electron configuration changes as you move down in this group?
What characteristic properties do the Noble gases (group 8A) share? How does atomic radius,
ionization energy and electron configuration changes as you move down in this group?
The Chalcogens are in group 6A of the periodic table, what characteristics properties do these
elements share? How do atomic radius, ionization energy and reactivity change as you move down
this group?
What characteristic properties do the Alkaline Earth metals in group 2A share? How does atomic
radius, ionization energy and electron configuration changes as you move down in this group?