1. Periodic Trends Summary, Periodicity Practice
Periodic Trends Activity 3
Periodic Trends Summary, Periodicity Practice

2. Explain why the periodic trends occur on the nuclear level
Objectives
Today I will be able to:
Analyze how the trends of atomic radius, ionization energy and electronegativity change across a period and down a family
Explain why the periodic trends occur on the nuclear level
Compare the atomic radius, ionization energy and electronegativity of 2 or more elements
Informal assessment: monitoring student questions and interactions as we complete the practice
Formal assessment: analyzing the students interpretations of the trends, practice and exit ticket
Common Core Connection
Model with mathematics
Look for and express regularity in repeated reasoning

3. Lesson Sequence Evaluate: Warm – Up
Explore/Explain: Why do the trends occur notes
Elaborate: Periodicity Practice Worksheet
Evaluate: Exit Ticket

4. Warm - Up For the following set of elements: Cl Sr Ge Ga
Circle the element that has the smallest atomic radius
Underline the element with the smallest ionization energy
Box the element with the greatest electronegativity value

5. Objective Today I will be able to:
Analyze how the trends of atomic radius, ionization energy and electronegativity change across a period and down a family
Explain why the periodic trends occur on the nuclear level
Compare the atomic radius, ionization energy and electronegativity of 2 or more elements

6. Homework STEM Fair Due Friday, November 14
Finish Periodic Trends Practice

7. Agenda Warm-Up Why do the trends occur discussion and notes
Periodicity Practice
Exit Ticket

8. Why do the Trends Occur?

9. Draw this table in your notes and discuss with your table (10 minutes)
Trend
How it changes
Why the change occurs
Atomic Radius
Across a period
Down a family
Ionization Energy
Electronegativity

10. Atomic Radius

11. Atomic Radius… Decreases across a period Why? Increases down a family
More protons in the nucleus, pulling the electron cloud closer to the nucleus
Increases down a family
More energy levels for the electrons to fill

12. Ionization Energy

13. Ionization Energy Increases across a period Why?
A greater number of valence electrons makes it more difficult to remove an electron
Decreases down a family
The electrons are farther away from the nucleus. They are less attracted to the atom making them easier to remove

14. Electronegativity

15. Electronegativity

16. Electronegativity

17. Electronegativity Increases across a period Why?
Atoms are closer to reaching stability so they want to attract electrons
Decreases down a family
The electrons are farther away from the nucleus in higher energy levels. They are not attracted to the nucleus as easily

18. Periodicity Practice Worksheet
Complete the worksheet using your notes. Ask Ms. Ose for help if you have questions we will review selected problems.
Periodicity Practice Worksheet

19. Exit Ticket For the following set of elements: Ba Mg O
Circle the element that has the smallest atomic radius
Underline the element with the smallest ionization energy
Box the element with the greatest electronegativity value