I went back to the American Chemical Society’s (ACS) Middleschool Chemistry curriculum and found this great activity for the periodic table that makes the students really look at the periodic table and understand what information the atomic number and atomic mass gives them. This is from Chapter 4, lesson 2: The Periodic Table. First I had them do a simple handout from Atomic Structure for Interactive Notebooks, where they label the atomic number, atomic mass, element name and symbol for one element. Then we filled out a partial periodic table putting in the number of protons, neutrons and electrons for the first 20 elements. This partial periodic table is provided in the ACS lesson. Since the proton number is equal to the atomic number I had them fill all of those in first and then since the atoms are neutral the number of electrons must be the same as the number of protons. Now that I’ve done the lesson, I think I should have done neutrons 2nd and left the electrons for last because the kids got confused and kept trying to add the number of protons and electrons to get the number of neutrons. If we had done the neutrons before the electrons, those numbers wouldn’t have been there to confuse them. To find the number of neutrons they had to look at the atomic mass, round it the nearest whole number and figure out how many neutrons they had to add to the protons to get the mass number. Since they had to do this 20 times, I think it was pretty well drilled into them by the time they finished.
All this was just setting them up for the activity, where each pair of students were given 20 cards with clues on them, like ‘this atom has 15 protons’, and then find the element that the card goes with. This caused a bit of chaos in the room as 10 kids ran around my kitchen trying to find elements but I think they learned quite a bit and had some fun doing it. My 16 year old son and I went through and found cards in the wrong place and kept handing them back to students who had finished with their cards. A couple of the students who really had this process down were given cards that discussed the electron shells and had more complicated clues. I think this would have worked a bit better if I had put color dots on the cards so I knew which teams had which cards. Then I could have given out a prize, or at least recognition for the team who got the most right – a little incentive for being more careful in their card placement. Another thing that would have decreased the chaos is have 2 teams at a time putting their cards up instead of everyone at once.