Color Coding the Periodic Table

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Objective

SWBAT easily identify the parts of the periodic table

Big Idea

A visual organizer helps students understand the organization of the periodic table.

Introduction

This is the first time in my chemistry class students have encountered a full periodic table.  They have been exposed to parts over time via the computer simulations, and have even done Lewis Dot Diagrams while learning atomic structure.

I use the California State Exam Periodic Table periodic table because it is the simplest, most up to date version I have found.  It is limited to just name, symbol, atomic and mass numbers per cell.  It also includes all 118 elements.  This is the periodic table students will use the rest of the year.  They can use their color coded PT on quizzes and exams until they add unauthorized information to it, or lose it, which is generally between 2 and 160 days.

This lesson is aligned to HS-PS-1-1:  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. In order to use the periodic table as a model, students must understand what it represents and the basic terminology used to navigate it.

We are also aligned to SP2: Develop and use models.  While this is a clearly developed model, the students' mental models to engage the PT are fresh.  So as they color code, they are developing their understanding and ability to use the model.

The final NGSS standards alignment is to a middle school level of the Patterns Cross Cutting Concept.  It states that graphs, charts and models are used to show patterns within data.  By color coding the periodic table, my students should be able to better integrate the patterns in elemental classification, and behavior, into their mental models of the periodic table.

Whole Group

15 minutes

The period begins with the periodic tables and instructions already passed out to each table.  The instructions will guide students through how to color code their periodic table to separate important sections (metals vs non-metals) and the various groups from each other.

I begin with asking students what they think our next unit will be about.  Those who have looked at the papers chime in "the periodic table" which is immediately usually followed with "Do we have to memorize it?"  I assure them that the days of needing to memorize the periodic table are over, but that we need to learn how to use it, and that's where we are starting today.

I have a student from each group come to the front of the room to get a colored pencil set, which includes two dark markers.  I explain to the class that they will be able to use this periodic table on quizzes and exams the rest of the year, so when they do color with the pencils, to lightly shade in the boxes so they can still read through them.

I then put a periodic table on the overhead and we do the first four steps of the instructions together.  I show them where to make the metal/non-metal dividing line.  Then I ask them how to do step 2: drawing a dividing line between the metals and non-metals, and have a student walk me through it in front of the class. The student will indicate that we should use a marker, and where to begin the line and where to end it.

I ask for another student to walk me through where to label the periods (answer: to the left of each period).  We have a discussion about whether or not the lanthanides and actinides get their own period numbers.  A student usually explains that they are part of periods 6 and 7 respectively, so we put arrows to show where they fit in.

I ask for a third volunteer to figure out where the group numbers are.  In this case, we cross out the roman numerals and the old "1A" style labeling, leaving just the numbers 1-18.  I ask for a final volunteer who can tell the class where to find Hydrogen, so they can outline it in pink.  The last step we do together is to shade the metalloids violet. 

Small Group Work

10 minutes

I then ask students to complete step 5 and shade the metals and non-metals as a table working together.  Since they already have set the metals/non-metals line, this should be relatively fast.  However, students do tend to get confused about the following:

  • Do the metalloids get multiple colors?
  • Is hydrogen a metal or non-metal?
  • What do I do with the Lanthanides and Actinides?

I generally respond to their questions with questions.  For the first two, I refer them back to what the instructions say.  For the last one, I refer them to "where did these elements come from?"  When they realize they were in the middle of the metals, it is easy for them.

Many students want to use the periodic table which is part of their school-issued agenda book.  This is fine, except some of the colors are different than the instructions on the assignment.  When a student makes an error in coloring, I give them a new blank and allow them to start over.

When students finish and reach the stop sign, I release them to finish the instructions individually or in pairs.

Pair/Individual Work

25 minutes

Students immediately bristle and ask "how do I know where the alkali metals are?"  I generally use some gentle sarcasm, referring them back to the instructions to use the computer (or mobile device, if they prefer).  Students can be very confused that there is no direct website to go to, and seem very uncertain about how to proceed.

I ask the confused students to highlight the words in each line of instructions that they don't know.  Once they have done this, I show them how they just identified what they will be searching for and direct them to the search engine of their choice.  I do warn them that the information on their periodic table may be more up to date than many websites, so they should extend any patterns they are noticing.

The final part I stress to each group is to make a good key.  Many students simply copy the sample key, which doesn't do much for them.  The students who make a good key initially are at a huge advantage.  This generally evens out over the next week as students realize they need a better key, and go back and revise and improve their own.

Before leaving, students turn in their colored periodic table so I can assess them using the checklist on the instructions page, and return them the next day.

While this activity can feel like a fluff activity, it is very helpful to my visual learners.  Students may have used the periodic table in the junior high, or not, and this serves as an orientation for them.  It also serves to provide a resource when doing our activities going forward.  We do not mandate students memorize the names of the groups, or differentiate between main-group elements and the transition metals.  However, many of our activities may still use these labels.

Students can navigate these activities with a well keyed and color coded table.  This lessens my need to scrub all the names out of pre-existing activities, and provides a safe resource to build confidence as students engage with the periodic table.