Teaching ionic compounds with manipulatives first

Teaching the formation of ionic compounds isn’t hard for most.  But starting with a visual activity before ANY lessons have occurred really helped the struggling students this year. The kids were engaged in solving problems using information they had from previous chapters.  Here is how I built the first part of the unit.

Make compounds with manipulatives

On the first day of the unit, which happened to be the first day back from Christmas break, I handed out decks of Who’s your ion? to groups of 4-6 kids. You can use your Lego manipulatives or paper versions if you have used those before.  All they had to do was spread the cards out over the table and then start balancing the charges by lining up the + and – signs along the edge of the cards.  The goal was to make all the positive and negative charges cancel out.  If they needed more than one cation, they had to match (using two Na+ cards rather than a Na+ and a NH4+).  Same for the anions. 

It was quite easy.  The kids made simple 1:1 compounds first.  Then I started making challenges to the class.  Every group needs to make a compound with three cards.  Four cards.  Then I challenged them to make lead (IV) phosphate.  They started balancing the charges.  And adding more cards.  And more cards.  I could see them start to wonder if this

would ever cancel out, which it finally does.

Write the formulas

Then I went to the whiteboard and individually called on groups to tell me the name of their compound (they have no idea how to name anything yet, I wanted them to start dreaming about how to do it) and also the formula.  This brought up the idea of using parenthesis to show multiples of polyatomic ions.  They were able, after very little practice, to convert the stable compounds they made with cards to real formulas.

Next year, I will have them all write the formulas for all the compounds they created on a piece of paper.  I just didn’t think of that in time for this year!

Introduce the Least Common Multiple Method

I have written a whole blog on this subject linked here.  But this year, by starting with the manipulative cards, the kids were able to more rapidly understand the LCM.  I wrote a few compound names on the board, and they wrote the formulas.  I haven’t introduced the idea of metals having more than one charge yet, so I was just using representative elements and ammonium for cations.

Play Who’s your ion?

The next day was our block day.  I put them in game groups and handed out decks of Who’s your ion?  They got 30 minutes to play the game.  I adjusted the levels of the game to match their current abilities.  They were engaged in the game of making stable compounds from their ion cards.  They were so engrossed that I actually left the room, went to the office, and invited the principal down to come watch and play.  That’s a risk, but it paid off.  When we got back to the room they were still playing away and probably didn’t even know I left.

Move into the rest of the compound chapter

Once they played for 30 minutes I simply took them into their notes and extended their understanding of the subject.  I loved starting the unit with these two activities.  The kids were solving problems and visualizing the formation of stable ionic compounds.  I particularly liked it for the lower kids as they got their hands on visuals first, which made the process much more effective.  It’s on the calendar for next year!

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Want to use a game that teaches balancing ionic charges as a manipulative? Try Who's your ion? What a family-style game that helps kids understand water solubility? Also, Who's your ion? This game can be used in multiple places in your curriculum to quickly connect kids to the subject. Check it out today!

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