Tag: metals

Questions Related to metals

Lustrous non-metal is :

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Diamond

  2. Iodine

  3. Sulphur

  4. Both A and B

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Correct Option: D
Explanation:

Non-metals do not have lustre. They do not reflect light from their surface. Non-metals have dull appearance. Diamond and iodine are two exceptions and are lustrous non-metal.

Which of the following is a lustrous non-metal?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Chlorine

  2. Nitrogen

  3. Iodine

  4. Florine

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Correct Option: C
Explanation:

Non-metals do not have luster. They do not reflect light from their surface (exception diamond and iodine). Non-metals have dull appearance.

Which non-metal has semi-conductor property?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Boron

  2. Carbon

  3. Silicon

  4. Magnesium

Show answer
Correct Option: C
Explanation:

Silicon is a tetravalent metalloid. Pure silicon is used to produce silicon wafers in the semiconductor industry. Pure silicon is an intrinsic semiconductor as it conducts electron holes and increases electrical conductivity. Silicon is doped with other microelements to increas its conductivity. It is used in transistors, solar cells, semiconductor devices.

Diamond and boron are soft non-metals.
chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. True

  2. False

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Correct Option: B
Explanation:

The given statement is false as diamond and boron are the hard non-metals.

Why are non-metals poor conductors of electricity?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. They have high melting point

  2. They vibrate at high speed

  3. They do not have free electrons

  4. All of above

Show answer
Correct Option: C
Explanation:

Non-metals are not dense enough and do not have enough free electrons to pass electricity efficiently. Electrons in non-metals are held tightly , they are no allowed to move freely .

Which of the following example is a poor conductor of electricity?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Oxygen

  2. Aluminium

  3. Gold

  4. Silver

Show answer
Correct Option: A
Explanation:

Oxygen is a non-metal. Non-metals do not have enough free electrons to pass electricity. Electrons in non-metals are held tightly, they are not allowed to move freely .

State True or False.
Non-metals are good conductors of heat.

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. True

  2. False

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Correct Option: B
Explanation:

Non-metals are poor conductors of heat because non-metal compounds do not have a metallic structure, which benefits heat conduction.

State True or False.
Non-metals have lustre. 

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Non-metals vary greatly in appearance. They do not have lustre. As it does not have any free electrons, light falling on non-metals does not reflect and hence non-metals are not shiny.

Why non-metals have a dull appearance?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. They have many free electrons

  2. They gain electrons easily

  3. They do not have lustre

  4. All of above

Show answer
Correct Option: C
Explanation:

Non-metals vary greatly in appearance. They do not have lustre. As it does not have any free electrons light falling on non-metals does not reflect and hence non-metals are not shiny. Hence, they have a very dull appearance.

Which of the following non-metal is hard yet brittle?

chemistry metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

  1. Graphite

  2. Selenium

  3. Sulphur

  4. Diamond

Show answer
Correct Option: D
Explanation:

Diamond is the hardest substance known to man with a hardness of 10.0. It is brittle sometimes because it grows in diamond shape crystals, sometimes there are tiny cracks or flaws in the diamond and a hard strike against the crack of course will cause the diamond to crack into many pieces. Crystalline materials have planes of variable shear and normal strengths hence, they fail on fracture mechanism. Also, crystalline nature makes them extremely strong at surface resisting scratch.