Science Lesson Plan · Grades 5–7

Atoms and Molecules Lesson

Teach students about atoms and molecules with this printable chemistry lesson. Uses a Lego analogy to explain how atoms are the building blocks of all matter. Covers the three subatomic particles — protons, neutrons, and electrons — and explains how atoms bond together to form molecules. Introduces elements, compounds, and the Periodic Table, with examples including water (H₂O) and table salt (NaCl). Includes comprehension questions and answer key.

Lesson Overview

Atoms, Molecules, Elements, and the Periodic Table

The lesson begins with a relatable analogy — atoms are like Lego bricks, and molecules are the structures you build from them. Students learn the roles of protons, neutrons, and electrons, how atomic number identifies each element, and how chemical bonds form when atoms share or transfer electrons.

The nine-page lesson pairs a reading passage with comprehension questions. Students learn to distinguish elements (one type of atom) from compounds (two or more types bonded together) and are introduced to how chemists use the Periodic Table to organize all known elements. A complete answer key is included.

How to Use This Lesson

1. Read the lesson passage together or have students read silently (pages 1–5). Ask students to explain the difference between an atom, a molecule, and a compound.

2. Discuss the Periodic Table. Show students where hydrogen, oxygen, carbon, and sodium are located and have them identify the atomic number of each.

3. Assign the comprehension questions (pages 6–8) independently. Review answers using the key on page 9.

Printable Resource

A classroom-ready PDF with everything in one printable resource.

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