I Wish I Had a Bag of Atoms

I try very hard to create learning opportunities for students to engage in "hands-on" inquiry. This works very well in physics with toy cars, potato cannons, and electric circuits. But when we start to learn about the structure of the atom, chemistry, and quantum mechanics, I am a little stumped. I wish I had a bag of atoms I could dump on the table for students to play with.

Recently, I was at Guildford Park Secondary to work with the science department in creating inquiry activities to align with the new BC Curriculum.  The teachers were frustrated about the lack of hands-on activities and labs for the grade 9 chemistry Big Idea: The electron arrangement of atoms impacts their chemical nature. This essentially means using the Periodic Table to understand how the electrons in the outer shell of atoms determine how chemical bonding will take place. Ionic and covalent bonds forming chemical compounds.

Students need to practice identifying atoms, maybe draw some Bohr models, and name the compound. Unfortunately, this usually means a whole lot of worksheets like these:

Now, these worksheets aren't horrible. They give students the practice they need. And they do require more than just naming compounds and writing chemical formulas. Students need to use the periodic table, draw Bohr models, and calculate some things. But there is not a lot of thinking required. I wish I had a bag of atoms!

I can hear you saying, "But wait! Don't we have atomic model kits? That's like a bag of atoms." The teachers at Guildford Park brought out the model kits and gave me a mini-lesson on ionic and covalent bonding (it had been so long since my last chemistry class, I had forgotten everything). I built some compounds and then asked, "How do I know which is ionic and which is covalent just by looking at it?" There was no visual way to tell. The bonds look identical.

An idea had been percolating in the back of my mind throughout our discussion. What if we created our own bag of atoms? It might look something like this:

What if students were given Bohr models and simply asked to create as many compounds as they could? Instead of a worksheet telling them to combine Hydrogen and Fluorine, they have to decide which elements they could combine. Instead of a worksheet asking them which type of bond it is, they have to decide how to bond the elements. Instead of a worksheet with 10 questions, they have to decide how many combinations they can make. The act of deciding changes everything. Students are doing the thinking. And it is deep thinking.

I would start with the 10 elements on the left that include the chemical symbol. Students must find a way to combine all the elements into compounds without having any left over (Helium is thrown in for fun).

Here is a sample of what this might look like:

Notice how the two types of bonds are now visually obvious. At the top, there are two ways to visualize covalent bonds. At the top left, the pictures have been trimmed back to allow the electrons in the Hydrogen atom to be taped onto the Oxygen atom overlapping the outer electron shell. At the top right, the sharing of electrons is emphasized by the use of brad pins to bond the two Hydrogen atoms. I like the brad pins because they demonstrate the strength of covalent bonding. At the bottom, an electron from the outer shell of the Berylium atom has been cut out and taped into the outer shell of the Oxygen atom. The elements are placed near each other to show the ionic "bond" through electrostatic forces between the ions.

Later on, I would repeat the process with the 10 unnamed elements on the right. In fact, I might choose to start with the unnamed elements and ask students to simply sort them however they wish. I imagine students will notice how many shells each element has and how many electrons are in the outer shells. Which is exactly how the Periodic Table is organized. That would lead naturally to a discussion of the Big Idea: The electron arrangement of atoms impacts their chemical nature.

I tried this out with Science Department Heads. I started with the worksheets, then brought out the Bag of Atoms. We talked about how the activity is different and improves on the worksheets. One comment encapsulates everything I wanted to accomplish. "We had to think."

Here is a link to my Bag of Atoms cards.

Special thanks to the Science Department at Guildford Park Secondary who were instrumental in developing the Bag of Atoms concept and activities