Sunday, November 15, 2015

How do we represent covalent compounds?

I shared this in a 2013 blog post, however, I have updated it some what and included a few more pictures.  This is an instructional strategy to help students explore the representation of covalent compounds through the use of a gallery walk. I recommend doing this activity before diving into notes/lecture (i.e. a type of inquiry lesson). You can use the activity as a reference point when speaking to students about bonding concepts during direction instruction.
How does this work? You will need to create a few electron dot structure posters of various covalent compounds. Create two for each compound - one showing the bonds as electrons (Lewis structure) and the other showing the bonds as lines (structural formula). Using the colors of the molecular models also helps (oxygen in red, nitrogen in blue, etc.) - which means you probably should print in color; however, printing in black and white that will not hinder the activity. 
Give or ask students to obtain two Post-It notes. One Post-It will be used for an "I notice..." statement. Students should look for patterns or things that look familiar.  In the picture below, someone wrote, "I notice N has 8 dots and each H has 2". 
The other Post-It will be used for an "I wonder..." statement. Students should pose questions about what they see on the poster. 
You can also use the activity to discover misconceptions / misunderstandings. For example, in the picture above, someone wrote, "This is a sickness", with an arrow pointing to the word ammonia. Clearly this student has pneumonia and ammonia mixed up; yet, it presents an opportunity to address this issue in class. 
Of course, you should be on the look out for potential inappropriate statements; although, I recommend referencing that during the activity expectations.  However, if you're worried about managing the comments, you could adapt the activity and have students complete the gallery walk in their interactive notebooks (if you use them) by writing the molecules you have posters for and create a two column page with the "I noticed..." and "I wondered..." sections. 
As an extension, you could have students pair up or get in groups of four to discuss what they each wrote and come to a group consensus on a  few or all of the molecules.  Have each group share out or contribute an idea to create a class anchor chart on chart paper (for "I noticed" and "I wondered").  Reference the anchor chart as you discuss covalent bonding/compounds and have students answer their own "I wondered" statements as you proceed through the unit. 
Another extension is adding some ionic posters to the mix.  You could do this during the ionic bonding unit or after you've talked about covalent bonding. 

Do you have any suggestions for enhancing this activity or an activity that you could incorporate with what I've shared here? Feel free to comment in the comment section

Need more resources for teaching covalent bonding and nomenclature? Check out the video and pictures below.

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