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ACTIVITY in Introduction, Elements, Periodic Table, Identifying an Unknown. Last updated January 29, 2024.
Summary
In this activity, students use imaginary elements to create a periodic table based on patterns in the known properties of those elements. They then use these patterns to predict the properties of an unknown element.
Grade Level
High School
NGSS Alignment
This activity will help prepare your students to meet the performance expectations in the following standards:
- HS-PS1-1: Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms.
Objectives
By the end of this activity, students should be able to:
- Explain periodic trends.
- Arrange elements appropriately based on their properties.
- Apply periodic trends to unknown elements to predict their properties.
Chemistry Topics
This activity supports students’ understanding of:
- Periodic table
Time
Teacher Preparation: 5 minutes
Lesson: 20 minutes
Materials
For each group:
- One set of element cards
- One blank periodic table template
Safety
- There are no special safety concerns for this activity.
Teacher Notes
- For this activity, students may work in groups of 2–3 or independently, though many students would likely benefit from sharing their ideas with peers.
- Before beginning this activity, explain to the students that their new periodic table should have appropriate trends across rows and groups of elements.
- Explain that the properties of the groups are not necessarily the same as the properties of real elements on the periodic table – however, students should use their understanding that groups have similar properties to determine how these elements should be arranged.
- In the Analysis Questions, students’ predictions for the masses of Ia and the unknown element may vary slightly, as the patterns are not exact. See answer key for acceptable ranges of answers.
- Depending on the amount of time you wish to spend on this activity, you could have the element cards pre-cut, or have the students cut them out themselves. You will want to print single sided to facilitate cutting out the element cards separately from the rest of the student handout.
- This activity could be paired with other complimentary AACT periodic table resources:
- Project: Repurpose the Periodic Table
- Activity: How the Periodic Table Organizes the Elements Video Questions
- Activity: Organizing the Periodic Table
- Activity: Mendeleev Video Questions
- Activity: History of the Periodic Table Video Questions
- Activity: Mendeleev’s Cards
- Activity: Mendeleev’s Periodic Table
- Activity: Aliens Activity
For the Student
Lesson
Background
The periodic table is a special way of arranging elements based on predictable patterns in their properties and characteristics. In this activity, you will create a periodic table using imaginary elements. This periodic table should have appropriate trends across rows and groups of elements.
Procedure
- On the next page, you will see a collection of elements along with their characteristics.
- Cut out each element card and arrange the elements in order based upon their characteristics, just like you would see on the periodic table. Use the attached periodic table template to organize the elements. (Note: Not all spaces on the template will be filled – there is a missing element!)
- After organizing your elements, use your periodic table to answer the analysis questions below.
- When you have finished, have your teacher check your work.
Analysis Questions
- Predict the state, color, and mass of the missing element. Explain your reasoning.
- Predict the mass of element Ia. Explain your reasoning.
- Predict the state, color, and mass of the element that will follow Az. Explain your reasoning.
- Bonus: Look at the element symbols used for these imaginary elements – do you notice something familiar about them? Explain the pattern and suggest a symbol (that does not match a real element symbol) for the missing element that fits this pattern.
Periodic Table Template
