Lesson 5

Lesson 5: Flame Tests 🔥

Identifying Metal Ions by Colour

🔥🔴🟡🟣💚

Learning Objectives:

2.45 – Describe how to carry out a flame test.
2.46 – Identify Li⁺, Na⁺, K⁺, Ca²⁺ and Cu²⁺ by their flame colours.

🏆 By the end I will be able to…

All: name the flame colour for each of the five metal ions.

Most: describe the flame test method step by step, including cleaning the wire.

Some: explain why the wire is cleaned and why each ion gives its own colour.

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Teacher Print Tools – Lesson 5

⏱️ Before We Start · 60 sec

Before We Start: Flame Tests in 60 Seconds

New to this? Here is everything you need for today — fast. (It is all on Side A of your bridge sheet if you want it on paper.)

Five metal ions — five colours

A flame test identifies the metal ion in a compound by the colour it turns a flame.

1. Clean a nichrome wire loop in concentrated HCl, then heat it until it shows no colour.

2. Dip the clean loop in the sample, hold it in a blue Bunsen flame, and read the colour.

3. Match the colour to the ion. Clean between every test — sodium’s yellow masks everything.

Whiteboards — 20 seconds: which ion is crimson red? Which is blue-green? Then we go straight into today’s colours.

⭐ Fab 4

The Fab 4 – Recall to Get You Started

Instructions: Multiple choice — in your books, write the letter you think is right for each one. No calling out. Reveal when ready.

1. Hydrogen

How do you test for hydrogen gas?

A) Burning splint → squeaky popB) Glowing splint → relightsC) Limewater → milkyD) Damp litmus → blue

✅ A) Burning splint → squeaky pop.

2. Carbon dioxide

What does CO₂ do to limewater?

A) Turns it blueB) Turns it milkyC) Bleaches itD) Nothing

✅ B) Turns it milky/cloudy.

3. The litmus pair

Damp red litmus turns BLUE. The gas is…

A) ChlorineB) OxygenC) AmmoniaD) Hydrogen

✅ C) Ammonia (NH₃) — the alkaline gas.

4. Today’s lead-in

Those tests find gases. How could you find the METAL in a solid compound?

A) Weigh itB) Put it in a flame and watch the colourC) Smell it

✅ B) Put it in a flame — different metals give different colours.

1. Oxygen

Which test is correct for oxygen?

A) Burning splint popsB) Glowing splint relightsC) Limewater goes milkyD) Litmus bleaches

✅ B) A glowing splint relights.

2. Chlorine

Damp litmus is bleached white. The gas is…

A) AmmoniaB) HydrogenC) ChlorineD) Carbon dioxide

✅ C) Chlorine (Cl₂) — it bleaches the dye.

3. Limewater

Limewater is a solution of…

A) Calcium hydroxideB) Sodium chlorideC) Copper sulfateD) Hydrochloric acid

✅ A) Calcium hydroxide.

4. Today’s lead-in

A flame test identifies the…

A) gas given offB) metal ion in the compoundC) mass of the sampleD) temperature

✅ B) The metal ion in the compound.

1. Negative results

Limewater stays clear. This tells you…

A) the gas is definitely CO₂B) the gas is NOT CO₂C) nothing at allD) the test failed

✅ B) The gas is NOT CO₂ — a negative result is still evidence.

2. The litmus pair

Why must litmus be damp for NH₃ and Cl₂?

A) so the gas can dissolve and reactB) to cool the gasC) to colour the paperD) it need not be damp

✅ A) The gas must dissolve in the moisture before it can react.

3. Write it (scaffolded)

Fill the gap: a flame test identifies a metal by the ________ it produces in a flame.

colourmasssmellsound

Word bank: colour · mass · smell · sound

✅ colour.

4. Why clean? (scaffolded)

Finish: “The wire is cleaned so that ________ from the last test cannot give a ________ colour.”

contamination / falseheat / brightwater / darkacid / new

Choose: contamination / false

✅ contamination / false — leftover ions would give a false colour.

Starter

🎨 Starter: Meet the Flame Crew

Your warm-up: tap a metal, then tap the colour you think it makes in a flame. A match locks green. A wrong tap just gives a tiny wobble — no harm, try again. Stuck? Tap Show the colour key any time.

Li⁺ → crimson red Na⁺ → yellow K⁺ → lilac Ca²⁺ → orange-red Cu²⁺ → blue-green

1 · Pick a metal

2 · Tap its flame colour

Pairs matched: 0 / 5

Aspire: as you match each one, say it out loud — “lithium makes a crimson red flame.” Saying it is how it sticks.

I Do

I Do: One Method, Five Colours (Spec 2.45 & 2.46)

Key Idea: a flame test identifies the metal ion in a compound by the colour it gives a flame. This appears on nearly every paper — five ions, five colours, free marks.

Li⁺ · Lithium

🔴 CRIMSON RED

LIpstick red 💄

Na⁺ · Sodium

🟡 YELLOW

NAcho yellow 🧀

K⁺ · Potassium

🟣 LILAC

King’s robe 👑

Ca²⁺ · Calcium

🟠 ORANGE-RED

CAmpfire 🔥

Cu²⁺ · Copper

💚 BLUE-GREEN

CUte statue 🗽

📋 The Method (worth marks on its own)

1. Clean a nichrome wire loop in concentrated HCl.

2. Heat it in the flame until it shows no colour (clean).

3. Dip the clean loop into the sample.

4. Hold it in a blue Bunsen flame and observe the colour.

5. Compare to the known colours and identify the ion.

🎯 Say this in the exam: “Dip a clean nichrome loop in conc. HCl, heat until no colour, dip in sample, hold in a blue flame, observe the colour.” That sentence is worth 4 marks.

🌟 Higher: electrons absorb flame energy, jump to a higher level (“excited”), then fall back — emitting light of a colour unique to that element.

Don’t write: calcium = orange · sodium = gold

Write: calcium = ORANGE-RED · sodium = YELLOW · lithium = pure CRIMSON

Lithium and calcium are the trap — pure crimson vs brick orange-red. Use the exact words.

Talk to your partner: which two colours are easiest to mix up — and what is the exact word for each? Be ready to match them next.

🔥 Observe

Observe: The Flame Lab

Watch & check: run all five tests. Before each one, say the colour you predict, then tap. Notice the wire being cleaned first every single time — that’s the method made visible.

🔥 THE FLAME LAB — tap a salt to flame-test it

Wire cleaned in conc. HCl before EVERY test · colours stay until reset

👀 Say it as you test: “I see a ____ flame, so the ion is ____.” Then jot the pair on your colour table.

🌟 Think: why must the Bunsen be on the roaring BLUE flame, not the yellow safety flame? Clue: the yellow flame glows with sodium — it would mask every test colour.

Ready check: cover the screen — can you name all five colours, Li to Cu, in order? If yes, you’re ready to match them yourself next.

🎬 Watch & Catch

Watch & Catch: The Real Flames

Now the real thing. As each metal is tested in the video, write its colour in your catch-table. Pause any time. You’re just writing what you see — you can’t get this wrong.

Video not loading? ▶ Open it on YouTube — the flame tests are in the first few minutes.

🎯 Colour-catch table

Write the colour you see for each ion:

Li⁺ · lithium

Na⁺ · sodium

K⁺ · potassium

Ca²⁺ · calcium

Cu²⁺ · copper

Li⁺ crimson red · Na⁺ yellow · K⁺ lilac · Ca²⁺ orange-red · Cu²⁺ blue-green

👂 Listen for: the wire being cleaned before every test, and why a blue flame is used (not the yellow one). Same method as the lab — now for real.

We Do

We Do: Build the Flame Test Method

Instructions: the six steps are jumbled. Tap them in the correct order to rebuild the method that earns 4 marks. Tap a wrong step and it just wobbles — no harm, try again.

Steps placed: 0/6

Jumbled steps — tap in order:

The method, in order:

🧡 Tip: the order is Clean → Check → Dip → Flame → Observe → Identify. Cleaning always comes first, identifying always comes last.

Start with cleaning the wire in conc. HCl; finish by comparing the colour to identify the ion.

Independent Work

Independent Work – Flame Tests

Instructions: Complete your printed worksheet at your level. You may use the colour table from the lab and the knowledge organiser. ❌ Never write “orange” for calcium — say orange-red.

Independent Work Timer

08:00

Foundation (Grades U–1)

Complete the colour table, then circle the right answers and a short red-flame scenario.

Middle (Grades 2–3)

Write the 4-step method, the five colours, and the Li-vs-Ca distinction, then a contamination exam question.

Higher (Grades 3–5)

Explain the electron chemistry, evaluate the technique, then a three-bottles 5-mark question.

📋 Scaffolding

Every pack includes the colour table, the method, sentence starters and word banks. Use them whenever you need them — that’s what they’re for.

🏆 Success Criteria

Foundation (U–1): I can name the flame colour for each ion and say what we clean the wire with.

Middle (2–3): I can describe the method and tell lithium and calcium apart by their exact colours.

Higher (3–5): I can explain why cleaning matters and why each ion gives its own colour.

🕵️ Plenary

🕵️ Plenary: Spot the Mistakes

Detective time. Now you know your colours — here is a student’s answer with three mistakes. Read it in your head, then tap each underlined claim to test it. Correct ones turn green; mistakes turn red and show the fix. No calling out!

“To carry out a flame test, I clean the wire loop with water, dip it in the sample, and hold it in a blue flame. Sodium burns red and lithium burns yellow, while copper burns blue-green.”

Mistakes found: 0 / 3

🧠 Detective’s hint: run the five through your head — Li crimson, Na yellow, K lilac, Ca orange-red, Cu blue-green — and check the cleaning step.

Aspire: for each mistake, don’t just spot it — say the correct version out loud, like a detective explaining the case.

Exit Ticket

Exit Ticket – Flame Tests

Knowledge check: Tap your answer to each question — instant feedback and a score at the end. Books closed, no notes!

Score: 0/6

🖨️ Print written exit ticket:

Name: ________________________ Class: __________ Date: ____________

🎯 Learning Objectives (2.45 & 2.46): Describe how to carry out a flame test, and identify Li⁺, Na⁺, K⁺, Ca²⁺ and Cu²⁺ by their flame colours.

🏆 Success Criteria — tick at the END of the lesson:

☐ I can name the flame colour for each of the five metal ions.

☐ I can describe the flame test method step by step.

☐ I can explain why the wire must be cleaned first.

Knowledge Organiser – Lesson 5: Flame Tests

Metal ion	Symbol	Flame colour	Memory trick
Lithium	Li⁺	Crimson red	LIpstick red 💄
Sodium	Na⁺	Yellow	NAcho yellow 🧀
Potassium	K⁺	Lilac	King's robe 👑
Calcium	Ca²⁺	Orange-red	CAmpfire / brick 🔥
Copper	Cu²⁺	Blue-green	CUte green statue 🗽

📋 Method (2.45): 1. Clean a nichrome loop in conc. HCl. 2. Heat until NO colour (clean). 3. Dip into the sample. 4. Hold in a blue Bunsen flame. 5. Observe the colour → identify the ion.

Key distinction: Li⁺ = PURE crimson red. Ca²⁺ = ORANGE-red, like a brick. The exam loves this pair — use exact colour words.

⚠️ Common mark-losers: writing “orange” for calcium (say ORANGE-RED) · “gold” for sodium (say YELLOW) · cleaning the wire with water (it is conc. HCl) · forgetting the wire must show NO colour before testing.

🎵 Memory hooks: LIpstick red = Li⁺ · NAcho yellow = Na⁺ · King's robe lilac = K⁺ · CAmpfire orange-red = Ca²⁺ · CUte green statue = Cu²⁺.

Arrival Task — The Fab 4

1. How do you test for hydrogen? Burning splint→pop / Glowing splint→relights / Limewater→milky

2. What does CO₂ do to limewater? ______________________

3. Damp red litmus turns BLUE — circle the gas: NH₃ / Cl₂ / O₂

4. Lead-in: How could you identify the METAL in a solid compound? ______________________

🧰 Word bank: burning · glowing · pop · milky · damp litmus · blue · bleached · flame · colour

🕵️ Plenary: Spot the Mistakes

This student made three mistakes. Underline each mistake and write the correct version next to it.

“To carry out a flame test, I clean the wire loop with water, dip it in the sample, and hold it in a blue flame. Sodium burns red and lithium burns yellow, while copper burns blue-green.”

1. ____________________ should be ____________________

2. ____________________ should be ____________________

3. ____________________ should be ____________________

🎬 Watch & Catch — Flame Colours

As you watch the demonstration, write the flame colour you see for each metal ion.

Metal ion	Symbol	Flame colour I saw
Lithium	Li⁺
Sodium	Na⁺
Potassium	K⁺
Calcium	Ca²⁺
Copper	Cu²⁺

Two things to listen for: 1. the wire is cleaned before every test; 2. a blue flame is used, not the yellow safety flame.

Scaffolding Sheet – Foundation (Grades U–2)

The Five Flame Colours

Ion	Colour	Memory aid
Li⁺	Crimson red	LIpstick
Na⁺	Yellow	NAcho
K⁺	Lilac	King's robe
Ca²⁺	Orange-red	CAmpfire
Cu²⁺	Blue-green	CUte statue

Sentence Starters

• To identify the metal ion, I would carry out a ____________.

• The flame colour was ____________, which shows the ion is ____________.

• The wire must be cleaned first because ____________.

Word bank

nichrome wire loop · concentrated hydrochloric acid · Bunsen burner · crimson red · yellow · lilac · orange-red · blue-green · contamination

Scaffolding Sheet – Middle (Grades 1–3)

Explain-It Toolkit

Key words you MUST use: nichrome · concentrated HCl · no colour · crimson · lilac · orange-red · blue-green · contamination · masks

Stems: “The flame was ___ so the ion is…” · “The wire is cleaned because…” · “Sodium masks other colours which means…”

The lookalikes

Li⁺ is a pure crimson red. Ca²⁺ is orange-red, like a brick. Always use the exact colour word.

Scaffolding Sheet – Higher (Grades 2–4)

Why each ion has its own colour

• Electrons absorb flame energy → jump to a higher level (“excited”).

• Falling back, they emit light of a specific wavelength → a colour unique to that element.

• Na⁺ emits so strongly that traces mask every other colour — hence rigorous cleaning.

Command words

DESCRIBE = say what happens · EXPLAIN = say WHY (use “because”) · COMPARE = similarities AND differences · METHOD = numbered steps.

5-mark frame (three bottles)

Per bottle: clean wire → TEST → COLOUR → ION. Then explain cleaning: name sodium and masking for the last 2 marks.

Independent Work – Foundation (Grades U–2)

Part 1 — Complete the colour table

Metal ion	Symbol	Flame colour
Lithium	Li⁺
Sodium	Na⁺
Potassium	K⁺
Calcium	Ca²⁺
Copper	Cu²⁺

Part 2 — Circle the correct answer

1. You clean the wire loop with: water / concentrated HCl / limewater

2. The wire is clean when it burns with: a yellow flame / NO colour / a green flame

3. A blue-green flame means the ion is: Na⁺ / Cu²⁺ / Li⁺

⭐ Part 3 — Exam practice [3 marks]

A student sees a crimson red flame. (a) Name the ion [1] (b) Name the equipment [1] (c) Why clean the wire first? [1]

Independent Work – Middle (Grades 1–3)

Part 1 — The method

Write the flame test method in 4 numbered steps:

Part 2 — Quick colours

Li⁺ = __________ · Na⁺ = __________ · K⁺ = __________ · Ca²⁺ = __________ · Cu²⁺ = __________

Part 3 — The lookalikes

How do you tell Li⁺ apart from Ca²⁺? Use the EXACT colour words.

⭐ Part 4 — Exam practice [4 marks]

A student tests NaCl (yellow), then KCl — but still sees yellow. (a) What went wrong? [2] (b) How to fix it? [2]

Independent Work – Higher (Grades 2–4)

Part 1 — The physics of the colour

Explain at the atomic level why different metal ions give different flame colours. Use: electrons · energy levels · excited · wavelength.

Part 2 — Evaluate

State one advantage and two limitations of flame tests.

⭐ Part 3 — Exam practice [5 marks]

Three bottles contain LiCl, NaCl and KCl. (a) Describe how to identify each [3]. (b) Explain why cleaning between tests is essential [2].

🌟 Part 4 — Application

A firework designer wants RED and BLUE-GREEN bursts. Which metal salts go in each — and why?

Exit Ticket – Flame Tests (Foundation U–2)

1) What colour flame does lithium (Li⁺) produce?

2) What colour flame does sodium (Na⁺) produce?

3) What do you dip the wire loop in to clean it?

Exit Ticket – Flame Tests (Middle 1–3)

1) A flame test gives BLUE-GREEN. Name the ion.

2) How do you know the wire is clean enough to use?

3) State all five flame colours and their ions.

Exit Ticket – Flame Tests (Higher 2–4)

1) Explain why different metal ions produce different flame colours.

2) A student gets YELLOW testing KCl. Explain what happened and the fix.

3) Describe the FULL flame test method.

Lesson 5: Flame Tests 🔥

🏆 By the end I will be able to…

Teacher Print Tools – Lesson 5

Before We Start: Flame Tests in 60 Seconds

Five metal ions — five colours

The Fab 4 – Recall to Get You Started

1. Hydrogen

2. Carbon dioxide

3. The litmus pair

4. Today’s lead-in

1. Oxygen

2. Chlorine

3. Limewater

4. Today’s lead-in

1. Negative results

2. The litmus pair

3. Write it (scaffolded)

4. Why clean? (scaffolded)

🎨 Starter: Meet the Flame Crew

I Do: One Method, Five Colours (Spec 2.45 & 2.46)

📋 The Method (worth marks on its own)

Observe: The Flame Lab

Watch & Catch: The Real Flames

🎯 Colour-catch table

We Do: Build the Flame Test Method

Independent Work – Flame Tests

Foundation (Grades U–1)

Middle (Grades 2–3)

Higher (Grades 3–5)

📋 Scaffolding

🏆 Success Criteria

🕵️ Plenary: Spot the Mistakes

Exit Ticket – Flame Tests

Knowledge Organiser – Lesson 5: Flame Tests

Arrival Task — The Fab 4

🕵️ Plenary: Spot the Mistakes

🎬 Watch & Catch — Flame Colours

Scaffolding Sheet – Foundation (Grades U–2)

The Five Flame Colours

Sentence Starters

Word bank

Scaffolding Sheet – Middle (Grades 1–3)

Explain-It Toolkit

The lookalikes

Scaffolding Sheet – Higher (Grades 2–4)

Why each ion has its own colour

Command words

5-mark frame (three bottles)

Independent Work – Foundation (Grades U–2)

Part 1 — Complete the colour table

Part 2 — Circle the correct answer

⭐ Part 3 — Exam practice [3 marks]

Independent Work – Middle (Grades 1–3)

Part 1 — The method

Part 2 — Quick colours

Part 3 — The lookalikes

⭐ Part 4 — Exam practice [4 marks]

Independent Work – Higher (Grades 2–4)

Part 1 — The physics of the colour

Part 2 — Evaluate

⭐ Part 3 — Exam practice [5 marks]

🌟 Part 4 — Application

Exit Ticket – Flame Tests (Foundation U–2)

Exit Ticket – Flame Tests (Middle 1–3)

Exit Ticket – Flame Tests (Higher 2–4)

🎓 TA Focus

🎯 Cold Call

🏆 Class Progress Board

🎉 Lesson Complete!