1. Periodic Trends Notes and Practice

2. Evaluation/ Assessment
Objective
Today I will be able to:
Analyze data to explain the trends of atomic radius, ionization energy and electronegativity
Apply periodic trends to solving problems
Evaluation/ Assessment
Informal assessment – Listening to group interactions and discussions as they complete the periodicity practice
Formal Assessment – Analyzing student responses to the exit ticket and periodicity practice
Common Core Connection
Build Strong Content Knowledge
Reason abstractly and quantitatively
Look for and make use of structure
Look for and express regularity in repeated reasoning

3. Lesson Sequence Warm – Up Evaluate: Observing Trends – Data Analysis
Informal assessment as students answer questions
Formal assessment collecting responses
Explain: Periodic Trends Notes
Elaborate: Periodicity Practice Worksheet
Evaluate: Exit ticket
Formal assessment

4. Warm - Up What is the electronegativity?
What happens to electronegativity as you travel across a period?
What happens to electronegativity as you travel down a group?

5. Objective Today I will be able to:
Analyze data to explain the trends of atomic radius, ionization energy and electronegativity
Apply periodic trends to solving problems

6. Homework Periodicity Worksheet Periodic Table Exam
Thursday, December 6th

7. Agenda Warm – Up Review Observing Trends Data Analysis Activity
Periodic Trends Notes
Periodicity Worksheet
Exit Ticket

8. Observing Trends – Data Analysis
Review

9. Periodic Trends Notes

10. Increases down a family (column)
Atomic Radius
Distance from the center of an atom to the outermost edge of the electron cloud
Decreases going across a period (row)
Increases down a family (column)

11. Atomic Radius Why does this trend occur?
Decrease across a period (row)
As you move across a period, more protons exert a pull on the electrons pulling them tighter, decreasing the radius
Increase down a family (column)
As you go down a family you are adding additional energy levels to put the electrons in
Adding energy levels makes the electron cloud larger

12. Atomic Radius

13. Decreases down a family (column)
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!
Increases going across a period (row)
Decreases down a family (column)

14. Ionization Energy Why does this trend occur?
Increase across a period (row)
As you move across there are more valance electrons, making the atom more stable. The atoms do not want to lose the electrons so it requires more energy to remove them
Decrease down a family (column)
The electrons are farther away from the nucleus so they don’t feel as attracted to the positive charge of the nucleus. Therefore, they require less energy to remove

15. Decreases down a family (column)
Electronegativity
The ability to attract electrons in a chemical bond
Increases going across a period (row)
Decreases down a family (column)

16. Electronegativity Why does this trend occur?
Increase across a period (row)
As you move across there are more valance electrons, making the atom more stable. The atoms want to attract an electron to become stable.
Decrease down a family (column)
The electrons are farther away in the orbital from the nucleus so it is more difficult for the positive nucleus to attract another electron.

17. Why don’t noble gases have values for electronegativity?
Stable
The outer shell is filled with 8 valance electrons
They do not need to attract another electron

18. Electronegativity

19. Complete Periodicity WS
Responses will be reviewed as a class

20. Exit Ticket
Arrange the following elements in the sequences of shortest radius to longest radius
I, Cl, F, Br
O, N, F, C