Models of the Atom  

Toni LaPoint, Bernita Cataldo, Tim Freed - NC Master Teachers

Introduction: -  Activity - ‘Think Tube’ -  gives students insight into what it could have been like to imagine the nature of an atom.  Class can appreciate the challenges associated with things that can’t be directly observed.

• On board - Dalton’s ‘Hard Sphere’ - model of an atom is uniform solid

Demonstration - Thompson’s Cathode Ray Tube - scientific discovery, the electron as rays were made up of charged particles carrying a negative charge.

• On board - Thompson’s ‘Plum Pudding’ - model of an atom is uniform positive charge solid with random negative charges spread throughout.

Activity - Atomic Target Practice - Rutherford Scattering and the Nuclear Atom

• Students (1class group) will shoot marbles at an unknown, unseen object and trace the path of a marble to predict the size and shape of the target under the board.

Simulation - pHet : Rutherford’s Scattering

(https://phet.colorado.edu/en/simulations/category/chemistry)

• Student groups will identify patterns and predict how this experiment will influence the model of the atom
• In their journal - individual students will sketch and explain their reasoning for their new model of the atom
• On board - Rutherford’s ‘Nuclear Model’  - model of an atom has a positive nucleus with electrons in empty space

Activity - Flame Test of unknown metals

• Student groups will perform a flame test on their metal and observe the color of the other groups
• Students will research why group obtained different results.
• Student groups will describe changes to the model of an atom

• In their journal - individual students will sketch and explain their reasoning for their new model of the atom

Simulation - pHet : Model of Hydrogen Atom - (Prediction - Bohr, check - show spectrometer, check - show electron energy level diagram, run)

(https://phet.colorado.edu/en/simulations/category/chemistry)

• Student groups  will reassess possible their model of the atom and predict why the groups obtained different result in their previous activity.
• In their journal - individual students will sketch and explain their reasoning for their new model of the atom
• On board - Bohr’s ‘Planetary Model’  - model of an atom has a positive nucleus with electrons in orbits

Simulation - pHet : Model of Hydrogen Atom - (Prediction - Schrödinger) 

(https://phet.colorado.edu/en/simulations/category/chemistry)

• Class will discuss change in animation
• On board - Schrödinger ‘Wave Mechanical model aka Electron Cloud Model’ - used mathematical equations to predict position of electrons in orbitals

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Science Essentials:

• Science Practices:

• Develop and using models - Construction and use of models and simulations to help develop explanations about natural phenomena
• Constructing explanations - The goal of science is the construction of theories that provide explanatory accounts of the material world.

• Concepts:

• Patterns - Observed patterns of form and events guide organization and classification
• Systems and System Model - Defining the system under study- -specifying its boundaries and making explicit a model of that system

• Disciplinary Core Ideas:

• Matter - Matter is made of particles

Models of the Atom  

Dalton’s Model:   ‘Hard Sphere’ 

        Draw ‘Hard Sphere’ Model                                        Describe the Model

 Thompson’s Model:   ‘Plum Pudding’ 

        Draw  ‘Plum Pudding’ Model                                        Describe the Model

Rutherford’s Model:   ‘Nuclear Model’

• Your groups will identify patterns and predict how this experiment will influence the model of the atom

• Write in your unit packet, your individual explanation of how the model of the atom will change as a result of the experiment

        Draw  ‘Nuclear Model’ Model                                        Describe the Model

Activity - Flame Test of unknown metals

• Student groups will perform a flame test on their metal and observe the color of the other groups
• Students will research why group obtained different results.
• Student groups will describe changes to the model of an atom

• In your unit packet,sketch and explain your reasoning for the new model of the atom

Simulation - pHet : Model of Hydrogen Atom - (Prediction - Bohr, check - show spectrometer, check - show electron energy level diagram, run)

(https://phet.colorado.edu/en/simulations/category/chemistry)

• Student groups  will reassess possible their model of the atom and predict why the groups obtained different result in their previous activity.

• In your unit packet,sketch and explain your reasoning for the new model of the atom

        Draw ‘ Bohr’s ‘Planetary’ Model                                        Describe the Model

Simulation - pHet : Model of Hydrogen Atom - (Prediction - Schrödinger) 

(https://phet.colorado.edu/en/simulations/category/chemistry)

• Class will discuss change in animation

        Draw Schrödinger ‘Wave Mechanica’l Model                                   Describe the Model

aka Electron Cloud Model’ Model