Which non-metal is a good conductor of electricity?
- A.Sulphur
- B.Graphite
- C.Phosphorus
- D.Iodine
Correct answer
Explanation
The correct answer is B, graphite. Graphite is an allotrope of carbon in which each atom is bonded to three others, leaving one electron per atom free to move through the layers, so it conducts electricity although it is a non-metal; this is why graphite is used for electrodes and in dry cells. Option A, sulphur, is a brittle, non-conducting solid, the standard example of non-metallic behaviour. Option C, phosphorus, does not conduct and its white form is stored under water because it ignites in air. Option D, iodine, is the non-metal that is lustrous, so it is the exception to a different rule and a favourite distractor here. Note also diamond, the other allotrope of carbon: it is the hardest natural substance and conducts heat extremely well, but it does not conduct electricity.
Read the full article: Metals and Non-Metals: Properties, Ores and Alloys
Practice Questions
View allCalamine is an ore of:
- A.Tin
- B.Magnesium
- C.Zinc
- D.Copper
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Calamine is zinc carbonate, and since it is a carbonate ore it is converted to the oxide by calcination, that is by heating in the absence of air, before being reduced to the metal.
Read the full explanation →Which of the following is NOT an alloy?
- A.Solder
- B.Silver
- C.Bronze
- D.Brass
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Silver is an element, a pure metal with its own place in the periodic table, so it cannot be an alloy; an alloy is a homogeneous mixture of two or more metals, or of a metal with a non-metal such as carbon.
Read the full explanation →Which of the following is the most ductile metal?
- A.Gold
- B.Copper
- C.Silver
- D.Iron
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Ductility is the property of being drawn into a wire, and gold is the most ductile metal known; it is also the most malleable, so a very small quantity can be beaten into an extremely thin sheet or drawn into a very long wire.
Read the full explanation →Brass is an alloy of:
- A.copper and tin
- B.copper and nickel
- C.copper and iron
- D.copper and zinc
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Brass takes the workability of copper and the hardness of zinc, resists corrosion and is easy to cast, which is why it is used for utensils, locks, taps, fittings and wind instruments.
Read the full explanation →Which metal is in the liquid state at room temperature?
- A.Sodium
- B.Mercury
- C.Lead
- D.Tungsten
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Mercury is the only metal that is liquid at ordinary room temperature, which is why it was long used in thermometers and barometers; it is also the metal that forms amalgams, alloys in which mercury is one component.
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