Chemistry is difficult to learn, but it tends to be easier for students who spend more time on consistent problem-solving practice. Many chemistry instructors provide students with practice tests to help guide their problem-solving and prepare for more significant assessments. Some instructors offer answer keys to these practice assessments, while others do not. An argument for providing answer keys is so that students can exercise effective self-quizzing strategies by attempting to solve the assessment first and then using the answer key to check their work and re-learn the concepts. Conversely, if answer keys are available, students may not learn how to independently solve the problems since they can simply study the answers keys. The “What’s Wrong with Me?” assignment is a remedy to the potential challenge described here.

“What’s Wrong with Me?” is an answer key activity that provides two different solutions for each question on a practice assessment.^{1} One solution is correct, while the other solution is incorrect. This activity increases students’ metacognition because they need to decide the right solution from the two options.

When developing your own “wrong” answers, it is best to generate errors consistent with those that students commonly make. Using “common” mistakes is most beneficial because students must exercise a high level of metacognition when critiquing them. It will help prevent repeating these sorts of errors on future assessments.

#### Examples of “Wrong” Answers

Secondary students often struggle with mole calculations that involve Avogadro’s number. Many students do not use their calculators correctly when entering scientific notation and frequently report answers with incorrect exponents. Considering this error, I usually include a wrong answer that involves this calculator error in mole calculations (figure 1).

**Figure 1:** A mole conversion practice problem answer key with a correct and incorrect solution.

Another frequent error at the secondary level is when students forget about Hund’s rule when drawing orbital diagrams. For this reason, I have often included orbital diagrams of group 5 or 6 elements in practice assessments (figure 2).

#### Students’ Impression of the Assignment

Students express a love-hate relationship with this type of answer key when surveyed. In general, students report that the assignment focuses them on learning the material more thoroughly but takes more time. It may be helpful to give students more time than usual when working with an answer key containing wrong answers.

**Figure 2:** An orbital practice problem answer key with a correct and incorrect solution.

#### References

Coppola, B. P., & Pontrello, J. K. (2014). Using errors to teach through a two-staged, structured review: Peer-reviewed quizzes and “What’s wrong with me?”. *Journal of Chemical Education*, 91(12), 2148-2154.

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## Comments 2

## Sharing worksheets

Your ideas are excellent I often show mistakes to help drive home a concept. Would you be willing to share your worksheets?

## Updated with a worksheet + answer key

Hi Yvonne!

Thanks! And, we updated the post with two documents. The first is a worksheet with practice questions related to the mole (Student Copy). The second is the answer key with correct and incorrect answers for that worksheet (Teacher Copy).

I have more of these sorts of assignments, but they are in need of some revision and tidying up before releasing them out to the world. I may add more if I ever get around to cleaning them up!

- Josh