First-Year Chemistry: A Sequencing and Lab Plan

Chemistry sections are often handed to teachers who trained in another science. If that is you this year, the questions are always the same: what order do the units go in, how many labs, what does a normal week look like, and how much marking is a lab report actually worth? Here is a plan built from what experienced chemistry teachers describe doing.

Two unit sequences that work

Neither of these is theoretical. Both are running courses, described by the teachers who run them, and they agree on the opening and diverge at the end. That divergence is the useful part.

Sequence A: atoms first

1. Course opening — rules, safety, measurement, significant figures, rounding
2. Atomic theory and structure
3. The periodic table
4. Chemical bonding
5. Naming compounds
6. Moles, molar mass and stoichiometry
7. Gas laws
8. Solutions
9. If time allows — acids and bases, thermochemistry, equilibrium, electrochemistry, nuclear chemistry

Sequence B: stoichiometry as the destination

1. Lab safety and equipment handling
2. Measurement, metric practice, particle models
3. The periodic table and the composition of the atom
4. Types of bonding and how they behave
5. Reactions and calorimetry
6. Stoichiometry
7. Equilibrium and acid–base chemistry, used as continued stoichiometry practice

Where they differ, and why it matters

Sequence A treats stoichiometry as a unit you finish and move past. Sequence B treats every unit after it as a pretext to keep practising it. If your students are going to struggle anywhere, it will be here — so the second framing buys you an extra term of practice without adding a single day to the calendar. Both sequences are defensible; only one of them keeps returning to the hardest thing in the course.

In year one, follow the textbook — but set hard deadlines

The most common advice given to teachers new to chemistry is to follow the textbook the first time through, provided you find it usable. It gives you a road map you did not have to build, and its labs have generally been run enough times to work. Use a sequence above to sanity-check the book's ordering rather than to replace it.

The load-bearing half of that advice is the second half: give yourself a hard deadline for each unit and accept that you will get to what you get to. The characteristic year-one failure is not choosing the wrong order. It is spending six weeks on measurement and never reaching stoichiometry at all.

A realistic week

Teachers new to chemistry often worry that a week built mostly on instruction and practice problems is too dry. It is worth knowing what an ordinary week actually looks like in a working chemistry classroom:

Three of five days on instruction and practice is normal and defensible. Chemistry is a modelling-and-practice subject and the practice has to happen somewhere. The lever is not fewer instruction days — it is what the other two days do. In the week above, the stations and the lab are carrying the load, and the instruction days exist to make them possible.

Where the content allows it, the usual variations are a simulation, a short research task on something students already argue about, a reading with questions, or a vocabulary game. You do not need one every day.

Labs: how often, in what order, and the early-lab gap

One lab a week, on a fixed day. A Friday lab is the simplest cadence that survives a real timetable, and fixing the day means students arrive dressed for it.

Teach the lesson, then run the lab. Inquiry-first has its advocates, but teachers who have tried both orders frequently report that students who already know the concept know what they are looking for once they are at the bench. In a first year, the safer default is to teach it first.

Expect an early-lab gap. If you follow an atoms-first sequence, the first couple of units do not lend themselves to interesting practical work — there is not much to do with atomic structure at the bench. Experienced teachers bridge it with standalone measurement labs that are genuinely engaging: finding the moisture content of popcorn, making slime, or anything that uses the balance and the concept of a mixture. If your school has a culinary programme, a kitchen chemistry collaboration covers the same stretch.

Lab reports without the marking overhead

Full formal lab reports every week will bury you, and they are not obviously worth what they cost. Two lighter formats come up repeatedly:

• Evidence-first claim and reasoning. A variant of claim–evidence–reasoning that starts with the evidence, on the grounds that evidence is what students actually have in front of them at the end of a lab. They record what they measured, state what it shows, then justify it.
• The three-level explanation. Particularly good for demonstrations. Students explain the same event three ways: what they observed, what the particles were doing, and what it looks like written symbolically as a chemical equation. It is short to mark and very hard to fake.

Lighter still: skip the report most weeks. Keep a lab journal where students record observations and answer the analysis questions, collect the journal, and mark only the analysis. And if you have come from another science, reuse the lab rubric you already have. A rubric that works for biology practicals is almost always general enough for chemistry, and rewriting one from scratch is time you do not have in September.

The vocabulary, unit by unit

Each unit below links to the topic page that collects its terminology, so you can send students to a list rather than a chapter:

• Opening and measurement — General chemistry: matter, mass, density, significant figures
• Atomic structure — atom, proton, neutron, electron, isotope, atomic number
• The periodic table — element, atomic mass, electron configuration, and the interactive table
• Bonding — chemical bond, ionic bond, covalent bond, ion, molecule, compound
• Reactions — reactant, product, catalyst, oxidation, reduction
• The mole and stoichiometry — mole, molar mass, Avogadro's number, limiting reactant, and the stoichiometry calculator
• Gases — Physical chemistry: gas laws, ideal gas law, and the PV = nRT calculator
• Solutions and acids — solution, concentration, molarity, solubility, acid, base, pH, titration

Questions