17/12/2025
🔥 FLAME TESTS — O LEVEL CHEMISTRY 5070 🔥
O Level Chemistry by Qadeer
Easy practical marks if you answer like an examiner 🧪✨
Flame tests appear again and again in:
Paper 2 (theory)
Paper 3 / Alternative to Practical
Yet many students lose marks due to poor wording ⚠️
Let’s fix that today 👇
🧠 Flame Colours You MUST Know (Chemistry O level 5070 Syllabus)
🔥 Li⁺ → 🔴 Red
🔥 Na⁺ → 🟡 Yellow
🔥 K⁺ → 💜 Lilac
🔥 Ca²⁺ → 🟠 Orange-red
🔥 Ba²⁺ → 🟢 Light green
🔥 Cu²⁺ → 🔵🟢 Blue-green
📌 No extra ions. No extra colours.
🧪 How to Perform a Flame Test (Examiner Method ✔️)
1️⃣ Use a clean splint / wire loop
2️⃣ Dip into the sample
3️⃣ Place in the hottest part of the flame 🔥
4️⃣ Observe the FIRST flame colour 👀
⚠️ Writing two colours when not asked = mark lost
📘 PRACTICE QUESTION 1 (Past Paper Style)
A solid compound is tested using a flame test.
A yellow flame is observed.
(a) Name the ion present.
(b) State why this flame colour may appear even if another metal ion is present.
✍️ Marking points examiner looks for:
(a) Sodium ion, Na⁺ ✔️
(b) Sodium gives a very strong yellow flame and can mask other colours ✔️
🧠 Keyword to include: “mask” / “hide”
📘 PRACTICE QUESTION 2 (Very Common!)
A compound gives a blue-green flame in a flame test.
Which ion is present?
A️⃣ Ba²⁺
B️⃣ Ca²⁺
C️⃣ Cu²⁺
D️⃣ K⁺
✅ Correct answer: C️⃣ Cu²⁺
❌ Writing “green” only = no mark
✔️ Write blue-green
📘 PRACTICE QUESTION 3 (Tricky Examiner Favourite)
A student observes a lilac flame during a flame test.
Name the ion present and state one precaution needed to ensure the result is correct.
✔️ Answer:
Ion: Potassium, K⁺
Precaution: Use a clean splint / remove sodium contamination
⚠️ HIGH-MARK EXAMINER TIPS
💯 Tip 1: Always link colour → ion
✔️ “Yellow flame observed → Na⁺ present”
❌ “Sodium present” (no evidence)
⚠️ Tip 2: Sodium is the BIGGEST trap 😳
🟡 Sodium’s yellow flame:
appears very easily
hides other flame colours
👉 If yellow keeps appearing, suspect contamination.
🔍 Tip 3: Avoid colour confusion
🟥 Li⁺ vs Ca²⁺
Li⁺ → red 🔴
Ca²⁺ → orange-red 🟠
🟢 Ba²⁺ vs Cu²⁺
Ba²⁺ → light green 🟢
Cu²⁺ → blue-green 🔵🟢
Never write just “green” ❌
❌ COMMON MISTAKES THAT COST MARKS
🚫 Writing wrong colour shade
🚫 Dirty splint
🚫 Writing long explanations
🚫 Guessing ion without observation
👉 Observation → conclusion = full marks ✔️
🤔 QUICK SELF-TEST (ENGAGEMENT BOOST)
Answer in comments 👇
1️⃣ Which ion gives lilac flame?
2️⃣ Why does sodium cause problems in flame tests?
3️⃣ Which ion gives light green flame?
💬 Comment like this: 1__, 2__, 3__
📌 FINAL EXAM ADVICE
🔥 Flame tests are easy marks, but only if you:
observe carefully 👀
use correct wording ✍️
avoid sodium contamination ⚠️
🔖 SAVE this post for revision
📘 FOLLOW for O Level Chemistry 5070 help
💯 Learn smart, score high
