Wednesday, August 14, 2013

CBSE Class 10 - Science - CH3 - Metals and Non-Metals

Metals and Non-Metals

Q & A

Q1: List any five physical properties of metals.

Answer: Physical properties of metals are:

  1. Metals are usually hard (exceptions are: sodium and potassium).
  2. These are sonorous.
  3. These are lustrous.
  4. Metals exhibit malleability and ductility.
  5. Mostly they are solids (exception is mercury)
  6. They exhibit high tensile strength.
  7. These have high densities.

Q2: Are metals electronegative or electropositive?

Answer: Metals are electropositive i,e. they form cations by loosing electrons.


Q3: Define Malleability.

Answer: Malleability is the property of a metal, by which it can be beaten into thin sheets.


Q4: Name a metal which can be cut with a knife?

Answer: Sodium



Q5: Give examples of metals which are found in liquid form at room temperature.

Answer: Mercury and Gallium


Q6: Define ductility. Give two examples of metals that exhibit this property.

Answer: Ductility is the property of a metal by which it can be drawn into thin wires. e.g. gold and silver.


Q7: Give an example of metal which is
      i. the best conductor of heat
     ii. the poor conductor of heat

Answer: (i) Silver  (ii) lead


Q8: What are metalloids? Give examples of metalloids.

Answer: The elements that exhibit properties of both metals and non – metals are called metalloids.
e.g. bismuth, silicon, germanium, arsenic, antimony, tellurium and polonium


Q10: What are minerals?

Answer: The Inorganic elements or compounds of various metals found in nature, associated with their earthly impurities are called Minerals.


Q11: Can metals be extracted from all types of minerals?

Answer: No. Some minerals may have high percentage of metals while other do not. 


Q12: What are ores?

Answer: Those minerals from which metals can be extracted profitably and conveniently are called Ores.


Q13: Define metallurgy.

Answer: The process of extracting metals from their ores followed by refining is known as metallurgy.


Q14: Give an example of non-metal which is lustrous.

Answer: Iodine


Q15: Give an example of a non-metal which is hard and has high melting point.

Answer: Diamond (allotrope of Carbon)


Q16: What is gangue and what is concentration?

Answer: Ores are usually associated with unwanted earthly matter called gangue (sand, clay etc.,) and the removal of this unwanted impurity is called concentration. The gangue has to be removed before the extraction of metals.


Q17:  Why do potato chips manufacturers fill the packet of chips with nitrogen gas?

Answer: Nitrogen provides an inert atmosphere to prevent chips from getting oxidised. Nitrogen is an antioxidant which prevents oxidation of substances and that's why such type of food material is flushed with nitrogen in packs.


Q18: Name any non-metal which is found in liquid state at room temperature.

Answer: Bromine


Q19(KVS): You are given two statements a and b, select the correct inference from this:

a. Metals conduct heat.
b. Diamond is the best conductor of heat.

i. Hence diamond is a metal
ii. Statement a is correct
iii. Statements a and b is correct
iv. None of the above

Answer: ii. Statement a is correct


Q20: Write differences between metals and non-metals based on physical properties.

Answer:

SNo.Physical PropertyMetalsNon-Metals
1.Physical StateMetals are solid at room temperature. Exceptions are mercury, cesium and gallium.Non-metals generally exist as solids and gases, except Bromine which is a liquid
2.Melting and Boiling PointsMetals generally have high melting point and high boiling point. (exceptions are Na and K)Non-metals have low melting pt and low boiling point. (exceptions are C, Si and B)
3.HardnessMetals are generally hard. (exceptions are Na and k which can be cut by knife).Generally soft. (exceptions is diamond, the hardest substance)
4.LustreBright metallic lustre. Usually silvery white appearance except gold (yellow) and Cu (pinkish red)Lack Lustre (exceptions are iodine and graphite which are lustrous)
5.DensityHave high density (exceptions: Na, K and Ca. Na and K float on water)Generally low density except diamond which has high density.
6.MalleabilityMalleable Non-malleable
7.DuctilityDuctileNon-ductile
8.TenacityUsually have high tensile strength. (exceptions are Na, K and Hg which are non-malleable, non-ductile and have low tenacity).Lack tenacity.
9.BrittlenessUsually hard but not brittle. (exception is Zn which is brittle at room temperature.)Generally brittle.
10.ConductanceIn general metals are good conductors of heat and electricity. (exception is Bi)Usually non-conductors. (exceptions are graphite and gas carbon)
11.SolubilityUsually do not dissolve in liquids except by chemical reaction.Dissolve in liquid solvents.
12.Alloy and AmalgamUsually make alloys and amalgams.Do not form alloys except carbon which alloys with iron to form steel.

(In progress...)

10 comments:

  1. Very nyce questions usefull!!!!!!

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  2. Very nyce questions usefull!!!!!!

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  3. Good questions..but more questions should be there for practice.

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  4. Very helpful! But more questions would've helped better.

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  5. This comment has been removed by the author.

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  6. Helped a lot thanks but a little more question would help more...

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  7. Helped a lot thanks but a little more question would help more...

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  8. Thanks a bunch! it helped me :)
    need more questions though.

    ReplyDelete