Keeping Up With the Trends
At a Glance
Discipline
- STEM
- Chemistry
Instructional Level
- College & CEGEP
Course
- General Chemistry, CHEM NYA
Tasks in Workflow
Social Plane(s)
- Group
Type of Tasks
- Writing
Technical Details
Useful Technologies
- Collaborative document for compiling answers and for teachers to check work
Class size
- Small (20-49)
Time
- Single class period (< 90 mins)
Inclusivity & Accessibility
- Variety of action & expression
Instructional Purpose
- Preparation & knowledge activation
Overview
Based on another ALA by Lori Jimbachian (The Right Tool for the Right Job), this is a collaborative activity designed to help students write rationales for observed trends in periodicity. Properties covered include atomic size, ionization energy and electron affinity, and the activity also asks students to compare isoelectronic species, successive ionization energies and more. Students are scaffolded through the process of writing a rationale via explicit models that require filling in the blanks using cards containing relevant terms. Later students can use these cards to help them construct their own rationales for other properties.
This activity is aimed at getting students to be able to write sound, scientific rationales for observed phenomena. This is an opportunity to help students learn to build up arguments using relevant terms that are appropriate to the context. Because students struggle with this, the idea of the cards are to help support the students by forcing students to recall terms from their pre-readings. With regards to the content, students will be able to master explaining the various periodic trends in atomic size, ionization energy, electron affinity and ionic size. The exercise is rooted in a scaffolded approach, first modelling an expert rationale, albeit with gaps to be filled with the activity cards, then by creating their own rationales using these same cards.
Instructional Objectives
- Write electron configurations for main-group elements;
- Identify the number of core and valence electrons in main-group elements,
- Describe, predict and explain trends in periodicity (atomic size, ionization energy, electron affinity and ionic size);
- Read and integrate knowledge from scientific texts;
- Work effectively and collaboratively in groups.
Workflow & Materials
Activity Workflow
Contributor's Notes
- Students not only support each other by writing rationales using scientific reasoning, but also practice discussing scientific phenomena openly.
- The scaffolded approach makes clear what is expected of a good rationale and the cards help reduce the cognitive load required to develop a rationale.
- Student preparedness and level of confidence will vary from person to person. Pre-quizzes or pre-class assignments could be used to accompany the readings;
- The instructor must be able to navigate groups in a timely manner to provide as prompt feedback as possible.
In answering student questions or in providing feedback on proposed student rationales, consider guiding only through questions. This forces the students to reevaluate their misconceptions and puts the onus on them to construct their knowledge.
Applied Strategies
Related Activities
Published: 05/02/2025
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