1. To the teacher:
This CPO Science PowerPoint presentation is designed to guide you through the process of presenting the lesson to your students. The presentation uses a 5-E teaching model: Engage, Explore, Explain, Elaborate, and Evaluate.
The PowerPoint Slide notes indicate where you may want to bring in various lesson elements such as quizzes, readings, investigations, animations, and practice materials. Additional science background information is provided in the slide notes where appropriate. You can view these notes by selecting “View,” then “Normal.” You will see the notes pane at the bottom of the PowerPoint workspace. Additionally, the slide notes are available as a separate document, accessible from the lesson home page.
The slides that follow are intended for classroom use.
About the slide notes:
The slide notes for this presentation are available in a separate document that you can print and look at while you use the slides. You can access the slide notes document from your teacher lesson home page.
Enjoy the lesson!

2. What’s the difference between K and Kr?
Find potassium (K) and krypton (Kr) on a periodic table. List their physical and chemical properties.
Why are these elements on opposite sides of the periodic table?
Are physical or chemical properties used to organize the periodic table?
ENGAGE: Students may be familiar with potassium as a nutrient in food. They may not recall that this is a soft, highly reactive metal. “Krypton” is the name of a planet in tales of Superman. The element krypton is in trace amounts in our atmosphere and used in lighting fixtures. From the graphic on the slide, students will see that krypton is a gas at room temperature whereas potassium is a solid. Point out to students that states of matter are physical properties. Guide a class discussion about chemical properties and explain that these are used to organize the periodic table. Pose this question to students: if potassium is a highly reactive metal on the far left of the table, what might be krypton’s chemical reactivity be if it is on the opposite side of the table? Ask students to explain their answer. Answer: Krypton is a noble gas with a complete octet of valence electrons. Potassium has only one valence electron, therefore it is chemically reactive.

3. Time to investigate! Complete the lesson investigation:
The Periodic Table
EXPLORE:
Lead the lesson investigation: The Periodic Table

4. Organization of the periodic table
The periodic table is organized in order of increasing atomic number.
Each horizontal row is called a period. Across a period, chemical properties gradually change.
Each vertical column is called a group. Groups have similar chemical properties.
Main group elements are groups 1–2 and 13–18. Transition elements are groups 3 through 12.
The inner transition elements, called lanthanides and actinides, are usually placed below the table.
EXPLAIN: Guide students in a discussion about how the terms in bold on this slide apply to the periodic table.

5. The periodic table
EXPLAIN: Use this slide to show the parts of the periodic table or quiz students about the parts. Address any questions or misconceptions they have about the periodic table.

6. More about organization
Groups of the periodic table include the alkali metals (group 1), group 2 elements, halogens (group 7), and the noble gases (group 8).
Metals are typically shiny, opaque, and good conductors of heat and electricity.
Nonmetals are poor conductors of heat and electricity.
Metalloids are metals that are moderate conductors of heat and electricity. They are on the border between metals and nonmetals.
The periods (rows) of the periodic table correspond to the energy levels in an atom.
EXPLAIN: This slide provides more details about the organization of the periodic table. Referring to the first slide of the lesson, point out to students that potassium is an alkali metal and krypton is a noble gas (a nonmetal). Next, ask why potassium and krypton are on the fourth row of the periodic table. Answer: They both have electrons in the fourth energy level. Potassium has only one outermost electron and krypton has eight. These electrons determine the chemical reactivity of the element.

7. Time for Practice! Complete the lesson practice activity:
The Periodic Table
ELABORATE: In this practice activity, students will apply what they have learned about the organization of the periodic table. Also, students will review energy levels and how they are filled by electrons.

8. Show what you know!
Try the lesson’s interactive quiz, or complete a quiz that your teacher can print out for you.
Hint:
You might want to review your lesson reading piece one more time before trying the quiz.
EVALUATE:
Print out the 10-question quiz for students to complete, or have students work individually at computers to complete the interactive quiz they can access from the multimedia lesson home page.