Introduction to Electron Orbital Levels

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Objective

SWBAT identify the 4 different electron orbital sublevels (s, p, d, & f) and correlate them to elements' location on the periodic table.

Big Idea

The organization of the periodic table is usful for identifying different electron energy levels, including orbital sublevels.

Why This Lesson?

This lesson helps students understand the various energy levels of electrons and lays the ground work in explaining why different elements want to gain or lose electrons to gain stability.  This understanding is necessary for students to be able to address both Performance Expectations HS-PS1-1 and HS-PS1-2.  

Students who are planning to enter college for a STEM field will be required to take a first year chemistry course in which electron configuration will be covered at a deeper level.  A general understanding of this concept will help prepare students for future chemistry work.

This lesson is structured to help students identify patterns in the Periodic Table so that they are not simply memorizing and are instead using the Periodic Table as a tool that they understand.  This strategy is part of the Next Generation Science Standards Crosscutting Concepts, addressing Patterns.

Warm-Up

5 minutes

While I take attendance, students do a warm-up activity in their composition Warm-Up/Reflection books.  I use warm-ups to either probe for students' prior knowledge about the day's upcoming lesson or to have them bring to mind and review what they should have learned during the Flipped Lesson recording the night before.  (To read more about Warm-Up/Reflection Books and Flipped Classrooms, please see the attached resource.)

Today's Warm-Up: "What are the names for the 4 electron orbital sublevels?"

In this case, the warm-up is asking students to remember from the homework assignment the night before that the 4 electron orbital sublevels are s, p, d, and f.  Potential reasons for incorrect answers are students not knowing that the term "electron orbital sublevel" refers to the s, p, d, and f orbitals or that students did not watch the assigned video.  I do not address any incorrect answers in today's warm-up because our lesson will address those issues directly.

Flipped Lesson Video:

If time permits, I walk around with a self-inking stamp to stamp the completed warm-ups indicating participation, but not necessarily accuracy.  On days when there is too much business keeping, I do not stamp.  Today's warm-up is particularly short in that students either know the answer or they do not--it does not require deeper level thinking.  Today, I will walk around and stamp student books if they have the correct answers.

I tell students that warm-ups are occasionally immediately checked and other times not.  At the end of each unit, I collect and spot-check Warm-Up/Reflection Books.  

As I am walking around stamping student responses, I might ask follow-up questions based on their answers (like "What is an orbital?" or "Did you have a chance to watch the video?").  

Applying Flipped Lesson Learning

15 minutes

After I have stamped the Warm-Ups, I ask students to name one orbital sublevel.  (I expect students to shout out answers at this point--we have developed a more conversational style of class discussion where when I ask questions, unless I preface the question with "Don't answer out loud--I just want you to think about this," students should vocalize their answers.)

I expect students to answer with s, p, d, or f, in some order.  As students name orbital sublevels, I list them on the whiteboard.  It may take some time before some students connect that "orbital sublevel" refers to s, p, d, and f.  Once one student correctly voices a sublevel, I expect the rest of the class to fall in rather quickly with the rest.

Then, I pass out the first part of today's assignment: Electron Orbital Sublevels on the Periodic Table.

I tell students that they can use the class sets of markers, colored pencils, crayons, or whatever supplies they have individually to choose 4 colors for color coding their periodic table handouts with the 4 different electron orbital sublevels.  I hold up a handout and ask the class if they notice anything on the bottom of the page, underneath the Periodic Table.  I am hoping that a student will respond with a description of the color coding key that is provided.  I tell students that they can use any colors that they want, as long as we can tell by using their key what color belongs with which orbital sublevel.

I remind students that during the flipped video they just watched as homework for last night, Hank showed which areas on the Periodic Table correspond to each orbital sublevel.  If students cannot remember where those areas are, or they want to double check before coloring, I allow them to use whatever resources they have available in class: class set of textbooks, internet access, youtube access via individual cell phones to the flipped video, lab partners, etc.  Students are directed to use me as a last check before using a different source.  

I also tell students that they have only 10 minutes to complete the activity and list their due time on the board as a reminder.

As students work, I walk around observing.  I ask students how they think they know where the sublevels are, what they thought about the flipped video, why did they choose the colors they did, and how they think that this information might be useful in following assignments.  If a student is clearly coloring the handout incorrectly, I might ask questions to see where the misunderstanding lies.  Does the student simply have sublevels switched (for example, coloring the f-orbital area the color designated for d-orbitals, and vice versa), which indicates a memory issue, or does the student combine multiple orbitals into one, which indicates an understanding issue?  If students are really off-track, I might give some one-on-one instruction and correct the mistakes, but if students have minor errors (switched orbitals), I will ask if they are sure about their answers and then allow them to figure out if it is incorrect (and why) by consulting other students.

At the end of the 10 minutes, or when the entire class is done (whichever comes first), I ask students to share what they have colored.  I do this by using a document camera and LCD projector so that we can project student work on the whiteboard and everyone can view the student's handout.  If there are no volunteers, I will randomly choose 3 and project each one (without the name showing).  We examine it as a class and if there are errors, we discuss what they are, and if it is correct we discuss how we know it is correct.  I expect my students to do most of the rationale in the discussion without needing too much input from me.

Writing Electron Configurations Trio Activity

25 minutes

For the next part of the lesson, it is important that students are grouped with their level of class.  My chemistry classes house both General level students and Honors level.  Many lessons need specific differentiation to meet the different expectation levels for the two different courses, and this is certainly one of them.  General Chemistry level students will work on electron configurations for elements numbered 20 and below, whereas Honors Chemistry level students should be able to complete electron configurations for any element on the periodic table.  As such, I will have my General Chemistry students sit on one side of the room and my Honors Chemistry students sit on the other side for today.  (Typically, I maintain a blended seating arrangement because the Honors students have a chance to solidify their understanding of topics by explaining them to General students, and General students have the opportunity to learn from their peers.)

I have a General Chemistry level version of the assignment and an Honors Chemistry level.  Students are told to get into groups of 3 on their respective sides of the room.  If we need to have a couple of pairs because the numbers of students do not accommodate groups of 3, then we do so.

I pass out a stack of assignment cards to each group.  The General Chemistry Cards are grouped as Students A, B, and C, while the Honors Chemistry Cards are grouped as Students D, E, and F.  Each card has 4 different elements listed (12 different ones for each set, divided into 3 students' worth) for which each student will be responsible to determine the electron configuration.  

I also pass out the individual recording handouts, one Electron Configurations recording sheet for General Chemistry and a different Electron Configurations recording sheet for Honors Chemistry.  Each student is responsible for completing a recording sheet.  Before I give students instructions for the assignment, I want to make sure that students can write electron configurations.  I have listed H, He, and Li as the first three elements on both recording sheets, so we can go over how to write electron configurations as an entire class.

On the white board, I show students the electron configuration for hydrogen and explain how we use the periodic table to figure it out, relating the rows on the table to the quantum number and the areas for sublevels that they had just colored on their first handouts.  I make sure that students know that the exponent on the configuration notation refers to how many electrons are contained in that specific quantum sublevel.

After demonstrating hydrogen, I also demonstrate (having the class guide my work with their suggestions) helium and lithium.

Then I ask one student from each trio/pair to get one student whiteboard and a dry-erase marker.  I give the students their instructions for the group work both verbally and written on the white board at the front of the class:

  1. Work individually on the electron configurations for elements on your card. (5 minutes)
  2. Starting with #4 on your recording sheet, go down the list taking turns sharing how you found the electron configuration for your elements.  Use the individual white boards to actually show your group how you started at 1s and moved through the entire configuration.
  3. If there are any disagreements within the group on the final electron configuration for any element, work through it until you reach a consensus.
  4. Record your answers on the individual recording sheet.

If students finish early, I will check their answers, and if they are correct, allow those students to roam the room helping other groups who might be stuck on disagreements or be stumped finding answers.

 

Whole Class Discussion

15 minutes

Once students are done with their group discussions (or 25 minutes has elapsed, whichever comes first), I ask students to come back together as an entire class.  I ask students to take out their grading pens.

I want students to correct their own work so that they can see exactly where they had misconceptions and make the correction in their thinking.  I also want a record of what their mistakes were, so when we have self-corrected work, I have students use a colored pen for making changes.  I grade them based on their corrected work, not on their original work (as long as it has been completed), so self-correcting should not be high stakes.

I scan the room to be sure that I see only colored pens in hand, and then proceed to call students up randomly to the front to use the whiteboard and complete the electron configuration for each element in the assignment.  I have General Chemistry students go down their list first, then the Honors Chemistry students complete their list.  This way, Honors students can get additional reinforcement for the basic element electron configurations and General students can be exposed to the electron configurations that include d and f orbital sublevels.

As we go through answers, if there is an answer at the board that is incorrect, I guide that student through fixing it if another student has not already started to voice how to fix it.  The rest of the students should be correcting any mistakes on their own individual papers.

After we are done, students turn in the day's work.

Student Reflection

5 minutes

If we have taken too much time during class discussion for corrections, this reflection can be skipped.

In student's Warm-Up/Reflection Books, students should spend about 3-5 minutes writing a response to the day's reflection prompt.  Prompts are designed to either help students focus on key learning goals from the day's lesson or to prompt deeper thinking.  The responses also allow me to see if there are any students who are missing the mark in terms of understanding.  The collection of responses in the composition books can also show a progression (or lack thereof) for individual students.  (For more information about how I use Warm Up and Reflection Books, please see the attached resource.)

Today's Reflection Prompt:  "How is the organization of the Periodic Table helpful in determining an elements electron configuration?"

Desired student responses should indicate that:

  • The Periodic Table is organized into s, p, d, and f orbital sublevel areas that are distinct
  • Rows on the Periodic Table help us determine quantum numbers (with "tricks" to use in d & f orbital sublevels expected from Honors students)
  • Counting boxes on the Periodic Table can help us figure out how many electrons are in each sublevel