Educational worksheet on metals and non-metals with questions about their properties, prepared by Mrs. Archana M K.

Let's solve each question from the worksheet "Materials – Metals and Non-Metals" step by step, along with explanations:

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1. The most ductile metal.

✔ Answer: Gold (Au)
🔹 *Explanation:* Ductility is the ability of a material to be drawn into wires. Gold is the most ductile metal because it can be stretched into very thin wires without breaking.

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2. The most malleable metal.

✔ Answer: Gold (Au)
🔹 *Explanation:* Malleability refers to the ability to be hammered or rolled into thin sheets. Gold is also the most malleable metal — it can be beaten into extremely thin foils.

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3. The metal which is best conductor of electricity.

✔ Answer: Silver (Ag)
🔹 *Explanation:* Silver has the highest electrical conductivity of all metals due to its atomic structure allowing free movement of electrons.

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4. The non-metal which is good conductor of electricity.

✔ Answer: Graphite (a form of carbon)
🔹 *Explanation:* Graphite is a non-metal but conducts electricity because it has delocalized electrons in its layered structure. It's used in electrodes and pencils.

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5. The hardest known substance.

✔ Answer: Diamond
🔹 *Explanation:* Diamond is an allotrope of carbon and has a rigid 3D network of covalent bonds, making it the hardest naturally occurring substance.

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6. Name three non-metals which have lustre.

✔ Answer: Iodine, Sulfur, Phosphorus
🔹 *Explanation:* While most non-metals are dull, some like iodine (shiny purple-black crystals), sulfur (yellow crystalline solid), and phosphorus (white or red, shiny) exhibit metallic luster under certain conditions.

> ✔ Alternative: Bromine (liquid, reddish-brown, has a shiny surface), but since it’s liquid, it may not show typical "lustre".

Best answer: Iodine, Sulfur, Phosphorus

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7. The metal which exists in liquid state at room temperature.

✔ Answer: Mercury (Hg)
🔹 *Explanation:* Mercury is the only metal that is liquid at standard room temperature (around 25°C). Its melting point is -38.83°C.

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8. The non-metal which exists in liquid state at room temperature.

✔ Answer: Bromine (Br₂)
🔹 *Explanation:* Bromine is the only non-metal that is liquid at room temperature. It is a reddish-brown fuming liquid.

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9. The metal which is poor conductor of heat.

✔ Answer: Lead (Pb) or Mercury (Hg)
🔹 *Explanation:* While most metals conduct heat well, lead is relatively a poor conductor compared to others like copper or silver. Some sources mention mercury as a poor conductor too.

> ✔ Best answer: Lead (commonly accepted as a poor conductor among metals)

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10. The metal which is best conductor of heat.

✔ Answer: Silver (Ag)
🔹 *Explanation:* Silver conducts heat better than any other metal due to high thermal conductivity, similar to its electrical conductivity.

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11. Name two non-metals which exist in gaseous state.

✔ Answer: Oxygen (O₂), Nitrogen (N₂)
🔹 *Explanation:* At room temperature, oxygen and nitrogen are gases. Other examples include hydrogen, chlorine, etc.

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12. Name two non-metals which exist in solid state.

✔ Answer: Carbon (C), Sulphur (S)
🔹 *Explanation:* Carbon (in forms like diamond, graphite) and sulfur are solid non-metals at room temperature.

> ✔ Alternatives: Iodine, Phosphorus

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✔ Final Answers Summary:

| Question | Answer |
|--------|--------|
| 1 | Gold |
| 2 | Gold |
| 3 | Silver |
| 4 | Graphite |
| 5 | Diamond |
| 6 | Iodine, Sulfur, Phosphorus |
| 7 | Mercury |
| 8 | Bromine |
| 9 | Lead |
| 10 | Silver |
| 11 | Oxygen, Nitrogen |
| 12 | Carbon, Sulphur |

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