Predicting the products of chemical reactions and then balancing those same reactions can be intimidating for grade-level chemistry students. I changed the order of my unit this year and saw improved results and fewer crazy answers on their test. It’s called “Stability First.” Give it a try and see if your students are more precise in their predictions. I think they will be.
Stability Early
We have a VERY rehearsed answer in my classroom about “why does this happen…” Every time I ask that question, the answer is “To become more stable.” To become more stable. To become more stable. They have it pounded into their heads from August. It makes sense, then, that the reason chemical reactions occur is to become more stable. Everything else has. This will too.
Reactions for Stability
At the beginning of the unit, as I’m sure many of you do, I create a story about the “chemical dance” in which the atoms are getting together, breaking up, swapping partners. This year, I made the stories even a little more cringy just to show how unstable some things are.
When the students start predicting the products, the question is, “How would these become stable?” Over and over. What needs to happen to make these new compounds stable? We practiced the different reactions types; combination, decomposition, single displacement, double displacement, and combustion. Everything to become more stable.
One key difference this year is that I didn’t worry about the appearance of more atoms or the disappearance of others at this stage. Everything was about stability.
Pro-tip: Come up with a catchy way to identify the diatomic elements. In my class, we call them “The Seven”. They start at # 7, make the shape of a 7 and there are 7. And why do they bond together? To become more stable.
Do Homework for Stability First
I had a large packet of homework where they had to predict a bunch of products. We went through the entire packet just completing the reactions stably. We didn’t even attempt to balance until the end. Stability first.
Once they have figured out how to write stable products, it is time to go back through and teach balancing equations. I found that teaching the unit in this order really helped to minimize the weirdness that comes when students are trying to balance and complete reactions at the same time.
Steps for Predicting Reactions
Teaching prediction in this order also gave the students a clearer set of steps.
1. Identify the reaction type. How will these atoms rearrange to become more stable?
2. Bond atoms together. How will these atoms bond to make stable compounds or elements?
3. Identify states in double displacement reactions. Are the products more stable than the reactants?
4. Balance.
By heavily preaching stability through the whole year, and then leading out with stability, this confusing unit became a lot clearer. Let’s just say I did it to become more stable myself.
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