Unit 1 — PS: Structures and Properties of Matter
Description
Students investigate the atomic composition of matter and the properties of substances. This unit covers how atoms combine to form molecules and extended structures, and how characteristic physical and chemical properties can identify pure substances. Students develop models to represent simple molecules and analyze data on substance properties before and after chemical reactions to determine whether a chemical process has occurred.
Essential Questions
- What is all matter made of?
- What is the difference between physical and chemical properties?
- What happens to atoms in chemical reactions?
- Describe the law of conservation of mass.
Learning Objectives
- Develop models to describe the atomic composition of simple molecules and extended structures.
- Use models of simple molecules to describe their atomic composition.
- Develop models of extended structures to describe repeating subunits.
- Analyze and interpret data on the properties of substances before and after they undergo a chemical process.
- Determine whether a chemical reaction has occurred based on changes in substance properties.
- Identify and describe correlation and causation relationships in chemical reactions.
- Make logical connections between evidence of chemical reactions and explanations of substance property changes.
- Use characteristic properties such as density, melting point, boiling point, solubility, flammability, and odor to identify pure substances.
Supplemental Resources
- Graphic organizers for for organizing information about atomic composition and molecular structure
- Index cards for for sorting and classifying substances by physical and chemical properties
- Chart paper for for displaying models of molecules and extended structures
- Printed word lists for for vocabulary related to matter, atoms, molecules, and chemical reactions
- Markers and colored pencils for for creating and labeling molecular models and diagrams
No core standards aligned for this unit.
Students read science and technical texts to gather and analyze information about matter and its properties, citing textual evidence to support conclusions and integrating information presented in diverse formats including diagrams, graphs, and models.
Students apply ratio and rate reasoning to solve real-world problems related to properties of matter, and use abstract and quantitative reasoning and mathematical modeling to analyze data from chemical and physical processes.
Formative Assessments
- Students develop and revise models of simple molecules and extended structures, demonstrating understanding of atomic composition.
- Students analyze and interpret data on substance properties before and after chemical reactions to identify changes.
- Students cite specific textual evidence from science texts to support conclusions about matter and chemical processes.
- Students create graphical displays and integrate quantitative information expressed in words with visual representations such as diagrams, graphs, and tables.
Summative Assessment
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Benchmark Assessment
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Alternative Assessment
Students may demonstrate understanding of atomic composition through a labeled diagram or physical model of a simple molecule (such as water or carbon dioxide) with teacher guidance, rather than a written explanation. Visual supports such as pre-labeled atom cards or partially completed molecular diagrams may be provided.
IEP (Individualized Education Program)
Students may benefit from graphic organizers and partially completed model templates when developing atomic and molecular representations, reducing the cognitive load of simultaneous drawing and conceptual processing. Providing pre-labeled diagrams, sentence frames for explaining property changes, and access to text-to-speech tools supports both comprehension of science texts and written output during data analysis tasks. Extended time and chunked directions help students work through multi-step investigations comparing substance properties before and after chemical reactions. Oral or visual alternatives to written explanations allow students to demonstrate understanding of key concepts such as density, solubility, and chemical change without being hindered by written expression demands.
Section 504
Students should be provided extended time during data analysis tasks and model-building activities, particularly when interpreting tables, graphs, or diagrams related to substance properties and chemical reactions. Preferential seating near instructional demonstrations and reduced-distraction environments support focus during inquiry-based investigations. Print copies of any board or projected content, including property data charts and molecular diagrams, ensure students can reference information without losing pace with instruction.
ELL / MLL
Teachers should use visual supports such as labeled diagrams of atomic structures, molecular models, and property data charts with icons to make the vocabulary of this unit — including terms like atom, molecule, density, solubility, and chemical reaction — more accessible. Simplified written directions paired with verbal explanation, and opportunities for students to respond through drawing or labeling models, reduce language barriers while still engaging with core scientific concepts. Connecting unit vocabulary to students' home language resources or bilingual glossaries, where available, strengthens comprehension of abstract matter and properties content.
At Risk (RTI)
Connecting the investigation of substance properties to familiar, everyday materials — such as water, salt, or baking soda — helps build entry points into abstract concepts like atomic composition and chemical change. Simplifying the complexity of data sets used during property analysis, while maintaining the core task of identifying whether a chemical reaction occurred, keeps learning accessible without removing conceptual rigor. Frequent check-ins during model-building and data interpretation tasks, along with structured graphic organizers that scaffold the relationship between evidence and explanation, support students in organizing their scientific thinking.
Gifted & Talented
Students who demonstrate early mastery of atomic composition and characteristic properties can be challenged to explore the relationships between molecular structure and observable physical or chemical properties at a deeper level, such as investigating why molecular geometry influences boiling point or solubility. Encouraging students to design their own comparative investigations of substance properties, or to critically evaluate the limitations of the atomic models they construct, fosters higher-order thinking beyond the unit's core expectations. Connections to real-world applications in materials science or chemistry — such as how engineers select materials based on characteristic properties — provide meaningful interdisciplinary depth.