Periodic Trends Graphing Activity
• Objective
– Today I will be able to:
• Predict and compare the relative radii for different
elements
• Analyze the trends of ionization energy,
electronegativity and atomic radius by completing a
graphing activity.
• Evaluation/ Assessment
– Informal assessment : Listening to group
interactions and discussions as they complete the
analyzing the periodic trends graphing activity
– Formal Assessment : Analyzing student responses
to the exit ticket and graphs
Lesson Sequence
• Warm – Up
• Explain: discuss the
definitions of the three
periodic trends of
ionization energy,
electronegativity and
atomic radius
• Explore: graphing the
data of periodic trends
– Informal assessment
listening to student ideas
about trends as they
graph data
• Elaborate: identify the
trends in noble gases
and across periods
– Informal assessment as
students predict trends
• Evaluate: Exit ticket
Warm - Up
Complete this warm-up on the note-card
Make a prediction.
Of the element pairs, which element do you
think will have a larger radius and why.
a) C or N
b) Cl or F
Objective
• Today I will be able to:
– Predict and compare the relative radii for different
elements
– Analyze the trends of ionization energy,
electronegativity and atomic radius by completing
a graphing activity.
Homework
• None! Enjoy the weekend!
Agenda
• Warm – Up
• History Notes
• Periodic Trends Graphing Activity
– Part 1 : Graph
– Part 2: Analyze
– Part 3: Summarize
• Exit ticket
History of the Periodic Table
Johann Dobereiner (1829)
• Law of Triads - in triads of elements the middle
element has properties that are an average of the
other two members when ordered by the atomic
weight
• Examples:
– halogen triad composed of chlorine, bromine, and
iodine
– Alkali triad composed of lithium, sodium, and
potassium
John Newlands (1864)
• Law of Octaves - states that any given
element will exhibit analogous behavior to the
eighth element following it in the periodic
table
Dmitri Mendeleev (1871)
• Developed the first Periodic Table
• He arranged his table so that elements
in the same column (groups) have
similar properties; increasing atomic
mass
Dmitri Mendeleev (1871)
•
•
•
Broke the trend of arranging elements solely
by their atomic mass
Wanted to keep elements with similar
properties in the same columns
Left gaps in his early tables; predicted
elements that had not been discovered
would fill in those gaps
- Ekasilicon  Germanium
- Germanium was discovered in 1886
Henry Moseley (1913)
• Periodic Law - when elements are arranged in
order of increasing atomic number, their physical
and chemical properties show a periodic
(repeating) pattern
• The periodic law is the basis for arranging
elements in the periodic table
Glenn Seaborg
• He reconfigured the periodic table by placing
the actinide series below the lanthanide series
• Awarded a Nobel Prize in 1951
• Element 106, Seaborgium (Sg), is named in his
honor
Periodic Trends Graphing Activity
Atomic Radius
• Distance from the center of an atom to the
outermost edge of the electron cloud
Electronegativity
• The ability to attract electrons in a chemical
bond
Ionization Energy
• Energy needed to remove an electron from an
atom
• High ionization energy means atoms hold their
electrons very tightly
Part I: Graphing Data
.
Graphing Directions
• You will work in a group of 3.
• Each person in the group is responsible for
graphing one trend (Atomic Radius,
Electronegativity or Ionization Energy)
• You will share the data analysis with the
members of your group
• You have 15 minutes to complete the activity
Part II: Analyzing the Data
Follow the directions to complete
part 2 for each graph.
Analyzing the Trend down a Family
Procedures:
• Begin with your atomic radius graph
• Connect all of the points for the noble gases to form a
line
– For the electronegativity graph connect the points for the
halogens
• Label this line on your graph
Q: What does this line tell you about the atomic radius
across the periodic table?
• Repeat this process for ionization energy and
electronegativity
Part III: Trends Summary
Complete the trends summary worksheet on
the back of your data sheet. Share the
graphs for each trend with your group to
predict how the trend changes across a
period and down a family
Exit Ticket
• Review your warm up.
• Were your predictions correct? Why or why
not.
• Why does the atomic radius follow the trend?
– Hint: think about what is happening on the
nuclear level