Teaching Middle School Chemistry
As a middle school teacher I find one of the hardest parts of my academic work is to really pinpoint exactly what my students need to know at this level. I’m a details person and I like to dig into the subjects that I teach. My fear is that I’m not laying out the big picture well enough and get stuck in the weeds with the details. But the big picture doesn’t work without enough details so I can’t ignore the details. Now you know the type of arguments I have with myself.
I love chemistry. I love elements. I love atoms. I love electrons. Yes, I’m a total geek, but I can’t help thinking that it’s beyond amazing that we know so much about things we can’t directly see or experiment with. Everything is through indirect methods and ingenious ones. I’m always amazed at the creativity that it took for people to figure out all that we know about atoms. (This is somewhat beside my main point; except, the fact that I think it helps to be excited about what you teach, otherwise teaching can really suck.),
So, back to what I do with teaching chemistry to 8th graders. Below I’ve laid out my outline of topics in the order that I think works, after 8 years of fiddling with it. Every system has limiting factors so in figuring out what to teach I had to respect my limits – this is an introductory level AND it’s only a UNIT of 8th grade, NOT a year long course in chemistry.
My development of this unit reflects my personal teaching philosophy:
I am dedicated to giving my students an opportunity to build a foundation of knowledge and skills to take into high school courses. I want two things for them:
1. They can walk into a high school course and feel confident that the knowledge they already have will support them in learning more. I am lucky in that I see my former students often and I ask them if I am doing a good job at this and they say yes. This comes from C students too. And, they are really thankful for it which is a major inspiration for me to keep pushing forward (otherwise, like I said, this job could really suck).
2. I don’t expect my students to recall all the facts they learned, but I do hope they learned about analysis, drawing logical conclusions, and writing with precision. I do hope that they remember about analyzing experiments – the role of constants and variables, testable questions, placebos and trial sizes. At least this skill may save them from believing everything that they read on the internet and falling for junk science.
So, the question is, what are the foundational concepts that set the stage for deeper learning in the future? Also, what skills do I want them to learn in middle school that will give them more confidence for higher level courses, in this case, chemistry?
Here is my outline of concepts taught with some main points/vocabulary stated as well. It is just an outline so imagine that I’m filling in the blanks with (hopefully) all of the right details. The list is generally in the order in which I teach these concepts. I’ve included links to some of the lessons/worksheets I created to teach this unit. I’d love to know what you teach for middle school chemistry. Please share your comments and suggestions!
Atomic Theory and Structure of an Atom
- Bohr’s model for understanding the atomic structure of the first 18 elements – protons and neutrons in the nucleus, electrons occurring at certain distances from the nucleus; these distances are energy levels (or shells); electron configuration rules for the 1st three energy levels. (no orbitals at this level)
- Atomic theory history – Democritus – Dalton – Thomson – Rutherford – Bohr – quantum mechanical model – Chadwick
Periodic Table and properties of elements
- Arrangement by atomic number
- Atomic mass – average atomic mass and mass of the most common isotope
- Periods = number of energy levels
- Groups – element in the same groups have similar chemical properties; valence electrons
- Properties of particular groups – metals, nonmetals, highly reactive/less reactive, halogens, noble gases, metalloids
Structure and Composition of Matter
- Atoms can bond and form compounds or molecular elements
- Ionic compounds – ionic bonds, ionic bonding, Lewis dot diagrams to model bonding, properties of ionic compounds, crystal lattice, formula units
- Covalent compounds and molecular elements – covalent bonds/bonding, Lewis dot diagrams to model bonding, properties of covalently bonded substances; molecule defined, chemical formulas
- Metallic bonding – electron sea model, this model can be used to explain the properties of metals (luster, malleable, ductile, conductive, high melting point)
- Mixtures vs. compounds and pure substances
Element, Compound or Mixture? Critical Thinking Exercises, Warm-ups or Exit Cards Free Sample Full Document
Matching Matter Worksheet: Is it an element, compound or mixture? Full Document
Introduce Chemical Bonding (Ionic, Covalent, Metallic) – Note-taking worksheets and practice exercises: Free Sample Full Document
Physical and chemical changes to matter
- Physical changes to matter – kinetic molecular theory explains why matter changes phases; properties of solids, liquids and gases at the particle level; basic concept about the intermolecular forces that hold particles close together in the solid and liquid state and how these forces are overcome based on how much energy particles have)
- Chemical change
- Chemical equations
- Endothermic and exothermic reactions
- Combustion reactions
- Acid/base reactions
- Law of conservation of energy and mass
- Balancing chemical reactions
- Signs of a chemical reaction
- Radioactive decay
- Alpha particle
- Beta particle
- Nuclear energy to produce electricity