The Periodic Table Worksheet - WordMint - Free Printable

Let's solve each question one by one based on the clues provided and match them with the correct elements from the list (A–T). We’ll go through each clue carefully.

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1. The simplest element
→ The simplest element is Hydrogen, which has just one proton and one electron.
✔ Answer: K. Hydrogen

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2. Has a nucleus with two protons and two neutrons.
→ This describes an atom with atomic number 2 (protons) and mass number 4 (2p + 2n). That’s Helium-4.
✔ Answer: E. Helium

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3. Has an atomic number of 3.
→ Atomic number 3 = Lithium
✔ Answer: L. Lithium

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4. Has a mass number of 9.
→ Mass number 9 could refer to Beryllium-9, which has 4 protons and 5 neutrons.
Be (Beryllium) has atomic number 4, and its most common isotope has mass number 9.
✔ Answer: R. Beryllium

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5. Has an atomic number of 5.
→ Atomic number 5 = Boron
✔ Answer: D. Boron

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6. Has 6 neutrons in its nucleus.
→ This means the mass number = protons + 6 neutrons.
We need to find an element where the mass number is about 6 more than atomic number.
For example:
- Carbon (atomic number 6) → if it has 6 neutrons, mass = 12 → common isotope: Carbon-12
So this refers to Carbon
✔ Answer: H. Carbon

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7. Has 7 neutrons in its nucleus.
→ Let’s look for an element with mass number = atomic number + 7
Try Nitrogen: atomic number 7 → mass number 14 → 7 protons + 7 neutrons → yes!
Nitrogen-14 is common.
✔ Answer: A. Nitrogen

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8. A gas we breath in.
→ We breathe in oxygen.
✔ Answer: I. Oxygen

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9. A poison put in toothpaste.
→ Fluoride (fluorine compound) is added to toothpaste to prevent cavities — though fluorine itself is toxic, fluoride ions are used safely.
So this refers to Fluorine.
✔ Answer: O. Fluorine

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10. Used in display lighting.
→ Neon gas is used in neon signs and display lighting.
✔ Answer: Q. Neon

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11. Found in salt.
→ Table salt is sodium chloride → contains chlorine
✔ Answer: S. Chlorine

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12. A metal which burns with a very bright flame.
→ Magnesium burns with a bright white flame.
✔ Answer: P. Magnesium

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13. A light strong metal.
→ Aluminum is lightweight and strong.
✔ Answer: G. Aluminium

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14. Used to make glass.
→ Silicon is a key component in making glass (especially silica, SiO₂).
✔ Answer: T. Silicon

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15. Has an atomic number of 15.
→ Atomic number 15 = Phosphorus
✔ Answer: J. Phosphorus

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16. Has a mass number of 32.
→ Mass number 32 → likely Sulfur-32, which has 16 protons and 16 neutrons.
Sulfur has atomic number 16.
✔ Answer: M. Sulphur

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17. A visible poisonous gas.
→ Chlorine gas is greenish-yellow and toxic. It’s a visible poisonous gas.
✔ Answer: S. Chlorine

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18. Has 22 neutrons in its nucleus.
→ Let’s find an element where mass number = atomic number + 22
Try Calcium: atomic number 20 → mass number 42 → 20p + 22n → yes!
Calcium-42 is a stable isotope.
✔ Answer: N. Calcium

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19. An alkali metal which catches fire in water.
→ Alkali metals include Li, Na, K, etc.
Potassium reacts violently with water, often igniting.
✔ Answer: B. Potassium

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20. Needed for bones and teeth.
→ Calcium is essential for bones and teeth.
✔ Answer: N. Calcium

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✔ Final Answers:

| Question | Answer |
|--------|--------|
| 1 | K. Hydrogen |
| 2 | E. Helium |
| 3 | L. Lithium |
| 4 | R. Beryllium |
| 5 | D. Boron |
| 6 | H. Carbon |
| 7 | A. Nitrogen |
| 8 | I. Oxygen |
| 9 | O. Fluorine |
| 10 | Q. Neon |
| 11 | S. Chlorine |
| 12 | P. Magnesium |
| 13 | G. Aluminium |
| 14 | T. Silicon |
| 15 | J. Phosphorus |
| 16 | M. Sulphur |
| 17 | S. Chlorine |
| 18 | N. Calcium |
| 19 | B. Potassium |
| 20 | N. Calcium |

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🔍 Notes:

- Some answers repeat (e.g., Chlorine and Calcium appear twice), which is fine since multiple clues can apply to the same element.
- For #17, chlorine is both a poisonous gas and found in salt, so it fits both #11 and #17.
- For #18 and #20, calcium appears twice — that’s acceptable.

Let me know if you’d like this formatted as a worksheet answer key!