Summary
This lesson serves as a stellar introduction lesson of what protons, neutrons, and electrons are and how they relate to each other. Students will study attractive forces in magnets to draw conclusions about the sub-atomic particles, diagram an atom, and discover how they can classify an atom based on its composition of protons, neutrons, and electrons. Although this lesson does not directly address ion or bond formation, the end of this lesson serves as an excellent segue into those topics.
Essential Question(s)
How can patterns of magnetism help explain the forces within an atom?
Snapshot
Engage: Students predict the contents of a black box, relying on their powers of observation without being able to see the inside. This mimics the study of related scientific principles.
Explore: Students observe attractive forces between magnets and record data.
Explain: Students use the data they collect to predict the relationships between protons, neutrons, and electrons. They apply these predictions by diagraming an atom.
Extend: Students use a PhET simulation to build atoms and make predictions about how particles influence element classification and net charge.
Evaluate: Students reflect on their learning and make a statement about how they can classify an atom based on its composition of protons, neutrons, and electrons to determine its element, and its charge status.
Materials
Black boxes (a class set of one black box per pair of students—see “Teacher’s Note: Creating Black Boxes” in the Engage phase for more information on how to build these)
Attractions and Subatomic Particles handout (attached; one per student)
Bar magnets (one per student)
Internet-enabled student devices (one per student)
Engage
15 Minute(s)
To begin the lesson, have students pair up and take one black box with their partners. Students should notice the boxes rattle.
Move to slide 4, and ask students how they can determine what the inside of the box looks like without opening it. Using the Question Generating strategy, have pairs brainstorm questions about barriers or challenges they anticipate that could prevent them from completing the task. Have students share their questions with the whole group and discuss possible answers.
Ask your students to tilt and rotate their boxes, listening to how the marble inside rolls around. Ask students if they hear the marble hitting any unexpected barriers inside the black box, given its shape.
Pass out a copy of the Attractions and Subatomic Particles handout to each student. This handout will be used throughout the entire lesson. First, ask students to look at part 1 of the handout, “Black Box.” Invite students to use their powers of observation and deduction to draw what they think is inside the box on the handout.
Move to slide 5 and read the essential question: How can patterns of magnetism help explain the forces within an atom? Move to slide 6 and, briefly, read aloud the learning objectives.
Explore
20 Minute(s)
Pass out two bar magnets to each pair of students. Before your students explore the attractive forces between the two magnets, ask them to look at part 2 of the handout, “Magnet Attractions,” and answer the two guiding questions:
How will you know if the poles are attracted to each other?
How will you know if the poles are repelled from each other?
Invite partners to share their answers.
Move to slide 7. Ask students to work with their partners and use their bar magnets to document the relationships between the positive and negative poles of the magnets. Students should fill out the chart on the second page of the handout as they experiment.
Allow students enough time to finish recording their observations and answer the next question on the handout:
What do the patterns and relationships you observed tell you? Does the data you recorded above align with your prior knowledge?
Explain
20 Minute(s)
Display slide 8, and share the definition on the slide with your students: “Sub-” is a prefix that means “smaller than.” What does subatomic mean?
Allow students to discuss this briefly and record an answer in part 3 of their handouts, “Subatomic Particles.” Then, move to slides 9-11, sharing the definitions of proton, neutron, and electron.
Proton: positively charged particle (shorthand: p+)
Neutron: neutrally charged particle, about the same size and mass as a proton (shorthand: n0)
Electron: negatively charged particle, much smaller than protons or neutrons (shorthand: e-)
These definitions include the academic language of protons, neutrons, and electrons. Move to slide 12. In a brief class discussion, ask students to predict the relationships between protons and electrons based on their experiences with the magnets in part 2 of the handout. Students should record their responses in part 3 of their handouts.
Next, invite students to work through part 4 of the handout, “Subatomic Particle Attractions,” with their partners. Students should use the table on the handout to predict the relationships between particles and then answer the following discussion questions:
Why do you think your prediction is correct? What data did you rely on and adapt for your prediction?
Why were neutrons not included in the table?
Ask for a few volunteers to share their responses with the class.
Continuing to work in pairs, have students move on to part 5 of the handout, “The Atom.” Students should read the paragraph about how protons, neutrons, and electrons interact with each other. Once they have completed the reading, they should label the atom diagram.
Consider having students check their labels against the information provided in the paragraph again. Provide them time to make revisions to their work as needed.
Extend
20 Minute(s)
Transition to slide 13. Invite students to navigate to the PhET Atom Builder simulation with the URL https://tinyurl.com/preucs2. Students should do the following to set the simulation up correctly (these directions can also be found on slide 14 and part 6 of the handout, “Atoms of Different Elements”):
Select “Atom.”
At the bottom, make sure the “Stable/Unstable” box is checked.
Also make sure the “Mass Number” and “Net Charge” drop-downs are expanded.
Have students use the simulation to answer the questions in part 6 of their handout:
Which subatomic particle defines what element the atom is?
Which subatomic particle provides stability to the nucleus?
What proton-to-neutron ratio generally (but not always) provides the best stability?
Move to slide 14 and share the information on the slide with your students: Any atom with a net charge of zero is called neutral. Any atom with a net charge other than zero is called an ion.
Ask students the guiding question, “How is net charge calculated?” Ask for volunteers share their responses. Have your students complete the remaining guiding questions in part 6 with their partners.
Evaluate
5 Minute(s)
Finally, move to slide 15, and ask students to complete part 7 of the handout, “Synthesis of Knowledge.” Here, students should write out how they can classify an atom based on its composition of protons, neutrons, and electrons to determine 1) its element, and 2) its charge status.
Resources
K20 Center. (n.d.). Question generating. Strategies. https://learn.k20center.ou.edu/strategy/167
The University of Colorado. (n.d.). ?Build an Atom?. PhET. https://phet.colorado.edu/sims/html/build-an-atom/latest/build-an-atom_en.html