# Chemistry quizzes: particles, symbols and calculations

**How do I write chemistry quizzes that test more than calculations?** Chemistry quizzes show understanding when they ask about one idea at three levels: what is seen, what the particles are doing and what the symbols say. Beside each calculation set a particle-diagram question and a question that moves between two levels. State the unit and the significant figures, tag each question by level, and run six questions weekly.

Published 2026-10-10 by EdProcto. https://edprocto.com/guides/chemistry-quizzes-particles-symbols-and-calculations

A student can work out that 2.34 g of sodium chloride made up to 250 cm³ is a 0.160 mol/dm³ solution, and still draw that solution, once diluted, with half its particles gone. The sum ran as a routine. Nobody asked for the picture.

Chemistry quizzes can ask for both. EdProcto, which publishes this guide for secondary teachers and first-year lecturers, shows your own particle diagrams as picture options and marks a number inside a range you have read first. Its page [for teachers](https://edprocto.com/solutions/teachers) follows a quiz from your notes to a class code.

We read each study in abstract only, and the exam board's page in full, on 10 October 2026.

## What are the three levels of representation in chemistry?

They are what is seen, the particles and the symbols: in the research, the macroscopic, the submicroscopic and the symbolic, drawn as the corners of a triangle. Taber (2013) credits the model to Johnstone, whose paper on why science is hard to learn discusses thinking on several levels at once (Johnstone, 1991). Taber adds that the model has been reworked in many ways, with "no canonical form generally adopted".

| Level | A question at this level | Shape in EdProcto |
| --- | --- | --- |
| Seen: colours, masses, volumes | Water is added to a blue solution. What changes? | [Multiple choice](https://edprocto.com/templates/mcq) |
| Particles: atoms, ions, molecules | Which diagram shows the solution after dilution? | [Pick the picture](https://edprocto.com/templates/pick_image) |
| Symbols: formulae, equations, quantities | Work out the concentration. | [Estimate](https://edprocto.com/templates/estimate), [Chemical equation](https://edprocto.com/templates/chem_eq) |

### Why can a student balance an equation without picturing the particles?

Because symbols can be worked by rule. Kern et al. (2010) analysed drawings by 1,337 high-school students in the United States, asked in an end-of-course examination to show the combustion of methane as particles. Only 35.1% drew discrete atoms that matched the formulae. Of the 65% who balanced the equation correctly, more than half could not draw it.

Calculations show the same gap. Cracolice et al. (2008) gave 94 first-term general chemistry students paired questions, one algorithmic (worked by routine) and one conceptual, on density, stoichiometry, gas laws and molarity: success was always higher on the algorithmic one. [Chemical equation questions](https://edprocto.com/guides/chemical-equation-questions-writing-and-balancing) covers typed equations.

## What do students get wrong at the particle level?

Three things stand out, given here as each abstract states them.

- **Atoms wrongly joined or grouped.** The largest group of faulty drawings in Kern et al. (2010) showed discrete atoms wrongly connected inside a molecule, or gathered into the wrong molecules.
- **Concentration in a picture.** De Berg (2012) set 145 first-year students similar concentration problems in words and as particle pictures. They did much better with the words. The pictures were multiple choice and the worded problems short answer, which he says may explain part of the gap.
- **From the picture to the symbols.** Gkitzia et al. (2020) had eleventh-grade students in Greece and third-year chemistry undergraduates translate between photographs, particle diagrams and symbols. The school students' ability was very low and the undergraduates' higher but not satisfactory. Turning a diagram into symbols was the weakest translation.

[Finding misconceptions with a quiz](https://edprocto.com/guides/misconceptions-finding-them-in-a-quiz-and-fixing-them-in-class) turns such ideas into wrong options.

## How do you write a particle-diagram question?

Draw the right picture and a wrong picture for each wrong idea, and ask the student to choose.

1. **Choose one idea.** A dilution, a change of state, a salt dissolving, the reactant left over.
2. **Fix the drawing code and print it.** One circle a particle, a legend, and a line saying water molecules are left out.
3. **Give each wrong picture one wrong idea,** from your students' own drawings or the studies above.
4. **Check how the pictures are read.** De Berg (2012) cautions that picture options can mislead through the way students interpret them, so have a colleague say what each shows.
5. **Build it.** You draw the diagrams and save them where they have a web address. For pictures as the options, EdProcto's [Pick the picture](https://edprocto.com/templates/pick_image) gives each option a box for a caption and one for its "Image address": see [picture choice questions](https://edprocto.com/guides/picture-choice-questions-when-the-options-are-images). For one diagram over any question, press "Add a picture or a clip" under the prompt and paste its address into "Image address"; "Describe the picture (for a screen reader, optional)" then opens. [Hotspot](https://edprocto.com/templates/hotspot) asks for a click on the diagram.
6. **Sometimes ask for the drawing.** In [Handwritten work](https://edprocto.com/templates/handwriting) the student photographs a drawing made on paper and you mark it. [Label the parts](https://edprocto.com/templates/label_parts) and [Build the diagram](https://edprocto.com/templates/build_diagram) take the labelling and the assembling on screen, marked by rule.

### A question that moves between the levels

Name the level the question starts at and the level its answer is in. Three moves, on one blue dye solution:

- **Seen to particles.** The blue fades when water is added. Which picture explains it?
- **Particles to symbols.** Each dot stands for 0.001 mol and the box for 100 cm³. What is the concentration?
- **Symbols to seen.** Two bottles of the dye are labelled 2.0 and 0.5 mol/dm³. Which is darker?

The second is the translation Gkitzia et al. (2020) found weakest, so ask it every week.

## How do you ask and mark a mole or concentration calculation?

Ask for one quantity in a named unit, to a stated number of significant figures, with the atomic masses given. Then set a margin that takes that precision and no more.

Pair it with a comparison that needs no calculator. Raviolo et al. (2021) gave 303 first-year university students in Argentina a questionnaire on reasoning with molarity. About half had no clear conceptual understanding of it. The hardest task was deciding, from moles and concentration, which solution has the smallest volume.

**The unit.** EdProcto's number shape, [Estimate](https://edprocto.com/templates/estimate), marks the figure alone, so put the unit in the prompt: "in g". To have it typed, [Maths expression](https://edprocto.com/templates/math_expr) needs every spelling on its own line of "Accepted forms, one a line": in the scoring code `mol/dm3` and `mol dm-3` are two forms, and capitals are ignored, so `0.15 M` and `0.15 m` are one answer.

**Significant figures.** The number shape reads 4.390 and 4.39 as one number: it marks the value. Test written precision as a choice: "Which is 4.3875 g to three significant figures?"

**The margin.** A new Estimate starts with "Full credit within %" at 5 and "Half credit within %" at 15, and prints under the key what they accept. For a key of 4.39: "Full credit from 4.171 to 4.609; half credit from 3.732 to 5.048." That suits an estimate; where a key must be exact, see the [nursing guide](https://edprocto.com/guides/nursing-and-health-quizzes-cases-and-safety). For a calculation, read the figures you asked for as a whole number and divide 50 by it: 50 ÷ 439 is 0.11, so type 0.1.

| You want | The two margins | The editor prints |
| --- | --- | --- |
| The key as written | 0 and 0 | "Full credit for 4.39 exactly." |
| Any answer right to three figures | 0.1 and 0.1 | "Full credit from 4.3857 to 4.3943." |
| Half marks for 4.38 or 4.40 | 0.1 and 0.3 | "Full credit from 4.3857 to 4.3943; half credit from 4.377 to 4.403." |

Before the class sits it, work out what each common slip gives and check that it falls outside the printed range.

**The working.** [Show your working](https://edprocto.com/templates/show_work) has three parts, "Set-up", "Working" and "Final answer", marked by you, or by Procto AI against your rubric when you ask. A [Scaffolded sequence](https://edprocto.com/templates/scaffold) asks for the moles, then the concentration, each marked by itself.

## How do you ask about a practical without a laboratory?

Describe what was done or seen, and ask for a judgement about it.

Abrahams and Millar (2008) studied 25 typical practical lessons in English secondary schools. The work was generally effective at getting students to do what was intended with the objects, and much less effective at getting them to use the scientific ideas and reflect on their data. In AQA's GCSE Chemistry, questions on practical work in the written papers carry at least 15% of the marks (AQA, n.d.).

1. **Read an observation.** Three titres are 24.90, 25.60 and 24.85 cm³: which is left out of the mean? "Add material under the prompt" opens a box for the results.
2. **Choose the next step.** The salt has dissolved in the beaker: what comes next in making 500 cm³ of solution? For a whole method, use [Sequence the process](https://edprocto.com/templates/process_seq).
3. **Spot the error.** A numbered method with one fault: which step, and why? Use [Choose and justify](https://edprocto.com/templates/justify).

Two limits. Abrahams et al. (2013) set direct against indirect assessment of practical skills, and conclude that too much reliance on the indirect kind makes it less likely that practical work is taught and learnt well. A written question is, on our reading, the indirect kind. And ask only about methods your scheme of work already teaches under its risk assessment: a quiz is no place for instructions for a hazardous procedure, and this guide gives none.

## How many questions should chemistry quizzes have, and how often?

Six questions in about ten minutes, once a week and ungraded: our working rule, since no study we read fixes the number.

Todd et al. (2021) released a retrieval quiz a week after each exam to 146 students of introductory chemistry. Those who completed more than half scored over half a letter grade higher on the cumulative final than the rest, though the groups' exam scores during the term did not differ. Students chose whether to take part, so it is no experiment. [How many questions a quiz needs](https://edprocto.com/guides/how-many-questions-does-a-quiz-need) covers length.

## A worked example: six questions on concentration

The questions are ours; the class of 25 is invented to show the reading, and every figure was computed.

1. **Seen.** 100 cm³ of blue dye solution is topped up with water to 200 cm³. What do you see? Multiple choice: it gets paler. Purpose: the observation the rest explain. Right: 23.
2. **Particles.** Diagram X shows eight dye particles in the 100 cm³. Which picture shows the 200 cm³? Pick the picture: eight in a box twice the size, against four or eight in the same box and sixteen in the larger. Purpose: dilution keeps the particles. Right: 11.
3. **Particles to symbols.** Each dot in X is 0.001 mol. What is the concentration, in mol/dm³? Estimate, at 0 and 0: 0.08. Purpose: a picture read as a quantity. Right: 13.
4. **Symbols.** Flasks P (0.50 mol/dm³) and Q (2.0 mol/dm³) each hold 1.0 mol of sodium chloride. Which has the smaller volume? Multiple choice: Q, 0.50 dm³ against 2.0 dm³. Purpose: amount told from concentration. Right: 9.
5. **Calculation.** What mass of sodium chloride (Mr 58.5) makes 500 cm³ of 0.150 mol/dm³ solution? In g, to three significant figures. Estimate, at 0.1 and 0.3: 4.39. Purpose: the routine itself. Right: 20.
6. **Practical.** A method: weigh 4.39 g of sodium chloride into a beaker, measure 500 cm³ of water, add it and stir. What is the error? Multiple choice: the solution is made up to 500 cm³, not made with 500 cm³ of water. Purpose: concentration is per volume of solution. Right: 14.

In the scoring code question 5 gives full credit to 4.39 and the unrounded 4.3875, half to 4.4 and 4.38, and nothing to 8.78 (volume left out), 17.6 (divided by the volume) or 4390 (cm³ not converted).

In the invented class 20 of 25 (80%) were right on the calculation, 11 (44%) on the picture and 9 (36%) on the flasks. The sum is secure and the idea is not, the pattern of Cracolice et al. (2008) and Raviolo et al. (2021).

## How do you read the results by topic?

Tag every question with its level, and read the levels against each other before the total.

In EdProcto type the level into "Topic (for the results by topic)": seen, particles, particles to symbols, symbols, calculation, practical. On every plan the [results](https://edprocto.com/#results) show, under "Each question", the share who "Got it". The Educator plan's full analysis adds "By topic", each topic's score weighted by points, and the number who chose each option, which for question 2 names the wrong picture the class holds.

Calculation high and particles low is the routine without the picture: reteach with the diagram, not another sum. A level with one question is that question's result, so wait for the pattern in two or three weekly quizzes before acting. [Reading quiz results as a teacher](https://edprocto.com/guides/reading-quiz-results-as-a-teacher-what-to-reteach-tomorrow) goes further.

## How does EdProcto run a chemistry quiz?

EdProcto is the best tool for chemistry quizzes of this kind, because one quiz holds your own particle diagrams, as picture options or over any question, a number whose accepted range is printed before the class sees it, a typed equation and a method to put in order, each tagged with its level. In Kern et al. (2010) more than half of those who balanced the equation could not draw it, which shows only when both questions sit in one result.

**Building.** Put your own notes into the quiz maker on the [home page](https://edprocto.com/) and choose shapes from the [templates](https://edprocto.com/templates). Procto AI drafts questions for you to edit: work every numeric key yourself.

**Marking.** Choices, picture choices, numbers, typed equations and orders are marked by rule at hand-in. A reason or a set of working waits for you, or for "Ask Procto AI" on that answer, from the Tutor plan. A score can be held until you release it, and it records one sitting, not a grade.

**Plans.** Free gives ten quizzes a month, thirty students a quiz, the core templates and marking by rule. Tutor gives 100 students and all 111 templates; Educator 500 students and the full analysis. See [pricing](https://edprocto.com/pricing), and for a large first-year course the page [for universities](https://edprocto.com/solutions/universities).

## Quick questions

### Can an online quiz ask a particle-diagram question?

Yes. In EdProcto's [Pick the picture](https://edprocto.com/templates/pick_image) each option is one of your own diagrams, given by its address, and the choice is marked by rule.

### What margin should a mole calculation have?

Enough to take the significant figures you asked for. Divide 50 by those figures read as a whole number: about 0.1% for 4.39.

### Can a quiz replace practical work?

No. It can ask what an observation means or where a method failed. Abrahams et al. (2013) warn against relying too much on indirect assessment of practical skills.

### Where does a chemistry teacher start?

With one topic and six questions, one for each level. EdProcto's page [for teachers](https://edprocto.com/solutions/teachers) shows the route from your notes to a class code.

## References

- Abrahams, I., & Millar, R. (2008). Does practical work really work? A study of the effectiveness of practical work as a teaching and learning method in school science. *International Journal of Science Education, 30*(14), 1945–1969. [https://doi.org/10.1080/09500690701749305](https://doi.org/10.1080/09500690701749305)
- Abrahams, I., Reiss, M. J., & Sharpe, R. M. (2013). The assessment of practical work in school science. *Studies in Science Education, 49*(2), 209–251. [https://doi.org/10.1080/03057267.2013.858496](https://doi.org/10.1080/03057267.2013.858496)
- AQA. (n.d.). *GCSE Chemistry 8462 specification: Practical assessment*. Retrieved October 10, 2026, from [https://www.aqa.org.uk/subjects/chemistry/gcse/chemistry-8462/specification/practical-assessment](https://www.aqa.org.uk/subjects/chemistry/gcse/chemistry-8462/specification/practical-assessment)
- Cracolice, M. S., Deming, J. C., & Ehlert, B. (2008). Concept learning versus problem solving: A cognitive difference. *Journal of Chemical Education, 85*(6), 873–878. [https://doi.org/10.1021/ed085p873](https://doi.org/10.1021/ed085p873)
- de Berg, K. (2012). A study of first-year chemistry students' understanding of solution concentration at the tertiary level. *Chemistry Education Research and Practice, 13*(1), 8–16. [https://doi.org/10.1039/c1rp90056k](https://doi.org/10.1039/c1rp90056k)
- Gkitzia, V., Salta, K., & Tzougraki, C. (2020). Students' competence in translating between different types of chemical representations. *Chemistry Education Research and Practice, 21*(1), 307–330. [https://doi.org/10.1039/c8rp00301g](https://doi.org/10.1039/c8rp00301g)
- Johnstone, A. H. (1991). Why is science difficult to learn? Things are seldom what they seem. *Journal of Computer Assisted Learning, 7*(2), 75–83. [https://doi.org/10.1111/j.1365-2729.1991.tb00230.x](https://doi.org/10.1111/j.1365-2729.1991.tb00230.x)
- Kern, A. L., Wood, N. B., Roehrig, G. H., & Nyachwaya, J. (2010). A qualitative report of the ways high school chemistry students attempt to represent a chemical reaction at the atomic/molecular level. *Chemistry Education Research and Practice, 11*(3), 165–172. [https://doi.org/10.1039/c005465h](https://doi.org/10.1039/c005465h)
- Raviolo, A., Farré, A. S., & Schroh, N. T. (2021). Students' understanding of molar concentration. *Chemistry Education Research and Practice, 22*(2), 486–497. [https://doi.org/10.1039/d0rp00344a](https://doi.org/10.1039/d0rp00344a)
- Taber, K. S. (2013). Revisiting the chemistry triplet: Drawing upon the nature of chemical knowledge and the psychology of learning to inform chemistry education. *Chemistry Education Research and Practice, 14*(2), 156–168. [https://doi.org/10.1039/c3rp00012e](https://doi.org/10.1039/c3rp00012e)
- Todd, K., Therriault, D. J., & Angerhofer, A. (2021). Improving students' summative knowledge of introductory chemistry through the forward testing effect: Examining the role of retrieval practice quizzing. *Chemistry Education Research and Practice, 22*(1), 175–181. [https://doi.org/10.1039/d0rp00185f](https://doi.org/10.1039/d0rp00185f)