Metals and Non-Metals
Q43. There are three materials X, Y and Z. X and Z are hard and
shiny, but Y is dull and not very hard. Identify the metals and non-metals from
X, Y and Z.
Ans. X and Z are metals.
Q44. Why wires are made of aluminum and copper and not of carbon
and copper are metals and can be drawn into wires. But carbon and sulphur are
non-metals and hence cannot be drawn into thin wires.
Q45. How phosphorus is stored?
Why is phosphorous stored in water?
What will happen if phosphorus is kept in open air?
Why do we store white phosphorus in water?
Phosphorus is a very reactive non-metal. It catches fire if exposed to air. To
prevent the contact of phosphorus with atmospheric oxygen, it is stored in
Q46. Why are wooden or plastic handles used for cooking utensils?
Why can’t we hold a hot metallic pan without a plastic or wooden
handle without getting hurt?
Ans. Wooden or plastic handles are used for cooking
utensils because they are bad conductors of heat and protects us from being
hurt while handling hot things.
Q47. Why there is difference in sound on dropping a metal coin
and a piece of coal?
Ans. Metals are sonorous i.e. they produce ringing
sound when struck hard whereas non-metals non-sonorous. Hence, on dropping a
metal coin, ringing sound is produced but no such sound is produced in case of
Q48. What does the ‘pop’ sound indicate in a reaction?
Ans. The ‘pop’ sound indicates the presence of
hydrogen gas. Metals react with sodium hydroxide to produce hydrogen gas.
Reactions of non-metals with bases are complex.
Q49. What is an element? Give example.
If a substance cannot be broken down further by chemical reactions, by cooling,
heating, or by electrolysis, it is called ‘element’. Sulphur is an element. So
is iron. Carbon, too, is an element.
Q50. “The atom of an element remains unaffected by physical
changes in the element.” Explain the statement with the help of example.
The atom of an element remains unaffected by physical changes in the element.
For example, an atom of liquid sulphur would be exactly the same as the atom of
solid or vapour sulphur.
Q51. How are elements classified?
An important classification of elements is in terms of metals and non-metals.
Most of the elements are metals. Less than 20 are non-metals. A few are metalloids
which possess characters of both metals and non-metals.
Q52. Why are electric wire made of copper?
Why are copper metal wires used to conduct electricity?
Ans. Copper metal wires are used to conduct
It is ductile and can be drawn into wires.
It is a good conductor of electricity.
Q53. Why can't copper displace zinc from its salt solution?
Copper cannot displace zinc from its salt solution. Give reason.
more reactive metal can replace a less reactive metal from
its compound in aqueous solution. Zinc is more reactive than copper. Therefore,
copper cannot displace zinc from its salt solution.
Q54. Can you store lemon pickle in an aluminium utensil?
pickle cannot be stored in aluminium utensils because lemon pickle contains
acids, which can react with aluminium (metal) liberating hydrogen gas. This can
lead to the spoiling of the pickle.
Q55. Complete the following reactions of iron and magnesium with
Iron (Fe) + Oxygen (O2) + Water (H2O) → ?
Magnesium (Mg) + Oxygen (O2) → ?
Ans. Iron (Fe) + Oxygen (O2) + Water (H2O)
Iron oxide (Fe2O3)
(Mg) + Oxygen (O2) → Magnesium oxide (MgO)
Q56. Explain reaction between sulphur and oxygen. What is the
nature of its oxide formed?
When sulphur burns in air, it combines with oxygen of air to form sulphur
dioxide (which is an acidic oxide).
+ Oxygen(O2) → Sulphur dioxide(SO2)
Q57. Can copper displace iron from iron sulphate solution? Give
Why copper cannot displace iron from iron sulphate solution?
more reactive metal can replace a less reactive metal from its compound in
aqueous solution. Copper lies below iron in the reactivity series i.e. iron is
more reactive than copper. Therefore, copper cannot displace iron from its salt