Cracking the Code: Writing Chemical Formulae
Cracking the Code: Writing Chemical Formulae
Lesduur is: 40 minOnderdelen in deze les
Cracking the Code: Writing Chemical Formulae
What do you already know about writing chemical formulae?
Learning Objective
At the end of the lesson you will be able to confidently write correct chemical formulae for simple compounds using symbols, valency, and rules.
Entry Ticket – Hook Question
If you mix salt into water, do you know what is happening at the chemical level? How are substances represented by their formulae in real life?
Pre-Assessment: Check Your Skills
1. What does the symbol 'O' represent on the periodic table? 2. Can you name the valency of sodium (Na)? 3. Write the formula for carbon dioxide.
Connect
4. Why do we need rules for writing chemical formulae? 5. How do you think atoms combine to form compounds?
Recall
Success Criteria
Explain: How chemical formulae represent substance composition. Interpret: Decode the meaning of a chemical formula. Compare & Contrast: Differentiate ionic and covalent compounds by their formulae. Evaluate: Judge the correctness of a chemical formula given the constituent atoms.
Key Terms
Lesson Development: Think-Pair-Share Activity
Individually, try writing the formula for magnesium chloride using the valency method.
Pair with a classmate and compare answers. Discuss the rules you used. Share one challenge or 'aha!' moment with the class.
Pair & Share
Think
Engage: Differentiated Activity
All students receive cards with different elements and valencies. Team task: Create the correct formula for a set of compounds. Share solutions and strategies.
Drop Everything and Read (DEAR)
Explore: Task 2 – Student Research
Investigate formulas for polyatomic ions (e.g., SO₄²⁻, NO₃⁻). Create a poster or handout explaining key rules and presenting some examples. Peer present and refine your explanations in groups.
AFL/Plenary: Reflection
Complete a quick quiz: - Name the formula for calcium oxide. - Identify one error in this formula: NaCl₂ - Reflect: What step in the formula-writing process was key for you?
Extended Learning
Create a concept map linking elements, valency, and formulae. Research a compound you use daily and present its formula, structure, and uses.
Exit Ticket – What Went Well?
Share one thing you understood clearly today about writing chemical formulae, and one question you still have.
Write down 3 things you learned in this lesson.
Write down 2 things you want to know more about.
Ask 1 question about something you haven't quite understood yet.
