Science lesson plan · 9th grade (Year 10 in England) · 30 minutes
Identify metal ions with flame tests and precipitates
Chemical reactions, acids and bases
CCSS NGSS.HS-PS1-2CCSS NGSS.SEP 3England: GCSE Chemistry: Chemical analysis (identification of ions)
Objective and success criteria
Students will: Identify metal ions with flame tests and precipitates.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Identify gases with laboratory tests
Leads to: the next skill in this area.
Materials: Teacher demo or video, Indicator color chart, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Identify gases with laboratory tests). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which gas gives this result: bubbled through limewater, it turns it milky? (hydrogen / oxygen / carbon dioxide / chlorine) → carbon dioxidePrompt: Each common gas has its own test.
- A gas puts out a lighted splint and turns limewater milky. What is it? (hydrogen / oxygen / carbon dioxide / chlorine) → carbon dioxidePrompt: Fire extinguishers sometimes contain this gas.
- Tests for gases: which statement is NOT true? (Oxygen relights a glowing splint. / Limewater is a solution of calcium hydroxide. / Oxygen gives a squeaky pop. / Chlorine may turn damp blue litmus red before bleaching it.) → Oxygen gives a squeaky pop.Prompt: Which gas pops and which relights a splint?
Hook · 3 min
- Drop an antacid tablet in water (or show a clip) and ask whether a new substance is being made.
- Share the objective: Identify metal ions with flame tests and precipitates. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: A flame test gives a lilac flame. Which metal ion is present?
- Step 1: Potassium compounds give a lilac flame.
- Step 2: So the answer is: potassium, K⁺
- Answer: potassium, K⁺
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- A flame test gives a yellow flame. Which metal ion is present? (calcium, Ca²⁺ / sodium, Na⁺ / copper, Cu²⁺ / lithium, Li⁺) → sodium, Na⁺Prompt: Fireworks use these colours.
- Sodium hydroxide solution is added to a solution and a brown precipitate forms. Which metal ion is present? (copper(II), Cu²⁺ / iron(II), Fe²⁺ / iron(III), Fe³⁺ / calcium, magnesium or aluminium ions) → iron(III), Fe³⁺Prompt: Each transition metal ion gives its own coloured hydroxide.
You do: independent practice · 7 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Sodium hydroxide solution is added to a solution and a blue precipitate forms. Which metal ion is present? (copper(II), Cu²⁺ / iron(II), Fe²⁺ / iron(III), Fe³⁺ / calcium, magnesium or aluminium ions) → copper(II), Cu²⁺Prompt: Each transition metal ion gives its own coloured hydroxide.
- Why should the wire loop be cleaned in acid before each flame test? (to add sodium / to remove traces of the last compound that could change the colour / to make the flame hotter / to stop the wire melting) → to remove traces of the last compound that could change the colourPrompt: Contamination gives false results.
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Identify gases with laboratory tests.
- Use concrete materials: teacher demo or video.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-9.
Free lesson plan from eurekami.com/lesson-plan-builder