Transcript Periodic Trends Analysis Cont.

Periodic Trends Analysis Cont.
• Objective
– Today I will be able to:
• Analyze the trends of ionization energy,
electronegativity and atomic radius by completing a
graphing activity.
• Explain the trends of ionic radius and electron affinity.
• 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, graphs and periodicity practice
Lesson Sequence
• Warm – Up
• Explain: Introduction to the
periodic table notes and
video clips
• 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
– Explain: Review the
explanation for the trends
of radius, ionization energy
and electronegativity
– Explain: Trends of ionic
radius, electron affinity, and
reactivity
– Elaborate: Periodicity
Practice
– Formal assessment
• Evaluate: Exit ticket
• Formal assessment
Warm - Up
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What is atomic radius?
How does it change down a family?
Why does this trend occur?
How does atomic radius change across a
period?
• Why does this trend occur?
Objective
• Today I will be able to:
– Analyze the trends of ionization energy,
electronegativity and atomic radius by completing
a graphing activity.
– Explain the trends of ionic radius and electron
affinity.
Homework
• STEM Fair
– Final Research Paper due Monday December 17
– In Class Presentations Wednesday January 23
– Periodicity Practice
Agenda
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Warm – Up
Finish Periodic Trends Graphing Activity
Discussion
Periodic Trends Notes
Periodicity Practice Worksheet
Exit ticket
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
Graph Data
Construct 3 graphs for ionization
energy, electronegativity and atomic
radius. Respond to questions on the
Worksheet.
Periodic Trends Notes
Atomic Radius
Distance from the center of an atom to the
outermost edge of the electron cloud
Increases down a group, decreases moving
from left to right across a period
Atomic Radius
As you move down a group, the number of
outermost electrons increases
As you move across a period, more protons
exert a pull on the electrons pulling them
tighter
Transition metals do not change size much
based on electron to electron repulsion in the
d sublevel
Atomic Radius
As you add an electron, there is an additional
proton that creates a force between the
nucleus and electrons that is stronger than the
repulsion between electrons, and therefore
the atomic radius decreases with additional
protons across a period
Atomic Radius
Ionization Energy
Energy needed to remove an electron from an
atom
High ionization energy means atoms hold their
electrons very tightly (noble gases)
Exactly opposite to atomic radius trend!
Smaller atoms can hold their electrons more
tightly together
Ionization Energy
Ionization Energy
• First Ionization Energy – energy needed to
remove the first electron
• Removing a second electron requires more
energy
Electronegativity
The ability to attract electrons in a chemical
bond
Increases across a period and decreases down
a group
Electronegativity
Ionic Size
Actual size of the atom
Ionic size is based on proton to electron ratios
When atoms lose electrons they get smaller,
when they gain electrons they get larger
Ionic Size
Electron Affinity
The energy change that occurs when an atom
gains an extra electron
Negative electron affinities indicate that the
elements do not require energy to gain an
electron, instead they release energy
Electron Affinity
The more negative the electron affinity, the
greater attraction for an added electron
Generally, nonmetals have greater electron
affinity than metals
Periodicity Practice
Complete the practice worksheet at
your seat. We will review selected
answers as a class and then hand the
assignment in.
Exit Ticket
• Explain the patterns in the trends down a
family and across a period for:
– Atomic radius
– Electronegativity
– Ionization energy