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

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 Part III: Trends Summary

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