SWBAT draw representations of atoms using assistance from ExploreLearning.

Modeling the nucleus and electron shells to learn how each particle contributes to the overall behavior of the atom.

This lesson builds upon the Build an Atom lesson. This also addresses HS PS1-1: *Using the periodic table as a model to predict properties of elements based on the patterns of electrons in the outermost energy level of atoms.*

Students are continuing to use computer based models, addressing Science and Engineering Practice 2: *Develop and use models*. To this point, students might have observed in the PHeT lesson that the electrons formed two distinct layers around the atom. Today is focused on connecting the structure of the atom to its behavior and the location of the particles. The benefit of Explore Learning is that, in addition to animating the electrons, it shows the third energy level providing a greater range of elements to use.

This allows us to integrate the *Patterns* Cross Cutting Concept, as students are looking for patterns in how the electrons orbit the nucleus, as well as how the particles interact with each other to make neutral, stable atoms.

The goal is that students will continue to connect these three ideas:

- Protons provide the identity of the atom, positive charge, and mass
- Neutrons provide stability for the nucleus and mass
- Electrons provide negative charge to make the atom neutral, and are located in layers around the nucleus.

10 minutes

One of my classroom emphases this year is on student organization. I start this period passing out the table of contents for our upcoming binder check. I give students 7 minutes to organize their materials. To facilitate the timing, I put the Online Stopwatch on the screen so students know when they will need to transition.

During this time, I pass out the Draw an Atom sheet. When the 7 minutes have elapsed, I remind students that binders are due tomorrow, and that they can organize at home now that they have started.

Many of my students used ExploreLearning (EL) during their Biology course the previous year. I orient students to the differences in EL compared to PhET using the projector. You can see how I accomplish this below.

Once students understand how to use ExploreLearning, and our goals for the activity, they move back to the computers to work on the simulation.

25 minutes

As students log into the computers, I move around the lab passing out our help cards and remind students to flip them when they get stuck. I also remind students of the need to log into Explore Learning before beginning.

As students work, I circulate the room to check their diagrams and understanding. When students get to Lithium, I ensure that their drawn model resembles that on the screen, with two electrons in the inner orbital and the third in the valence shell. The organization of the electrons is the key takeaway of the lesson, so I am constantly checking student drawings for accuracy, as seen in this student example.

The biggest obstacle to accuracy lies in students trying to take shortcuts and not label the nuclear particles, or to not recognize the layering of the electrons and just spraying them in random orbit around the nucleus. To help students who aren't recognizing the orbitals, it is helpful to animate the atom so students can have the visual of the electrons orbiting in distinct shells. Comparing this to a race, I talk about how runners must remain in their lanes.

To differentiate up, I ask the more advanced students to make predictions of the last three elements in pencil before completing the bottom row on the computer.

The end timing of this section of the lesson is fluid. As students finish, I have them flip the paper over to work on the vocabulary matrix. This removes some time pressure for students who can feel behind due to slow processors and loading times for our computers.

15 minutes

As students finish their computer simulation, they transition to the Vocabulary Matrix. This is modified from Marzano and Pickering and serves as a graphic organizer for students to review prior to the quiz the next day.

I urge students to do it without resources at the start, to learn what they actually know, before turning to their resources to fill in the gaps. Students are generally fast to complete the location, charge and mass of each particle, but struggle some with the purpose.

While students are working, I refer their thinking back to the two lab simulations, PhET and EL, "What happened when they added each particle?" I also explicitly refer to how this is the same thought process they should use when taking the quiz tomorrow: think about each simulation and how atoms changed when they added specific particles. Does it go in the nucleus or the outside? Did it affect the charge or the mass? How did it affect the charge or mass? Focus on the patterns you've observed over the past two days of simulations and experimentation.

This student example is a good example of how students will complete the purposes, versus my key. It is crucial students understand the concepts, but the vocabulary doesn't have to be perfect.