Periodic Trends Notes and Practice

1. Periodic Trends Notes and Practice

2. 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 • Informal assessment as students answer questions • Formal assessment collecting responses • 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. 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. 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. 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