Students can use Class 7 Science Curiosity Extra Questions and Chapter 4 The World of Metals and Non metals Extra Question Answer to prepare effectively at home.
Class 7 Science Chapter 4 The World of Metals and Non metals Extra Questions
Class 7 Science Chapter 4 Extra Questions on The World of Metals and Non metals
The World of Metals and Non metals Class 7 Very Short Question Answer
Question 1.
Name two metals.
Answer:
(i) Iron, (ii) Copper.
Question 2.
Name any two non-metals used in daily life.
Answer:
(i) Oxygen, (ii) Carbon.
Question 3.
Give one use of aluminium foil.
Answer:
To wrap food items.
Question 4.
Name the metal used in electrical fittings.
Answer:
Copper.
Question 5.
How malleability benefit everyday life?
Answer:
Malleability allows materials in touseful products like aluminium and silver to be formed foil and decorative sheets.
Question 6.
What does Magnesium Ribbon produce after burning ?
Answer:
Magnesium oxide, due to reaction of oxygen with magnesium in air.
Question 7.
Why is sodium stored in kerosine oil?
Answer:
Because Sodium (Na) reacts with the water and oxygen producing heat, hence kerosine prevents exposure of sodium to air as well as moisture.
Question 8.
Why is phosphorus stored in water?
Answer:
Because the phosphorus catches fire if it is exposed to air in atmosphere.
Question 9.
Oxides of non-metals are acidic or basic?
Answer:
The oxides of non-metals are acidic in nature.
Question 10.
Name some non-metals.
Answer:
Chlorine, sulfur, oxygen, nitrogen, carbon, iodine etc.
Question 11.
Define an element.
Answer:
An element is defined “as a substance that cannot be broken into simpler substances”.
Question 12.
Which property of metals allows them to be drawn into wires?
Answer:
Ductility
Question 13.
Name a non-metal used in water purification.
Answer:
Chlorine
Question 14.
Which non-metal is essential for respiration?
Answer:
Oxygen
Question 15.
Solution of which non-metal is applied on wounds as an antiseptic?
Answer:
Iodine
Question 16.
Name the gas which is formed on burning of sulfur?
Answer:
Sulfur dioxide gas
Question 17.
What do we call the shine present on the surface of metals?
Answer:
Metallic luster
The World of Metals and Non metals Class 7 Short Question Answer
Question 1.
Why are metals essential in daily life ?
Answer:
Metals essential in daily life due to their distinct properties like lustrous nature, high strength, heat and the electrical conductivity etc.
Question 2.
What is the role of carbon and oxygen in everyday life? (V.Imp.)
Answer:
Oxygen is necessary for breathing, we cannot survive without oxygen. The carbon compounds such as fats, carbohydrates and proteins are essential for growth and energy.
Question 3.
What is an alloy? What is its use in our daily life?
Answer:
An alloy is “a mixture of a metal and a nonmetal, two or more metals.” It is necessary for everyday use as in utensils and modern tools and industries, zirconium used in atomic energy and titanium in aerospace.
Question 4.
Name any two substances which behave differently from the metals in air an water. Write their properties also.
Answer:
Phosphorous and sulfur are two non-metals that behave differently in air and water. Mostly they are dull and soft in their appearance. Sulfur forms sulfur dioxide when it burns in air. SO2 if dissolved in water, forms sulfurous acid. The phosphorus is stored in water because it catches fire when exposed to air in atmosphere.
Question 5.
Sodium metal is kept in kerosene but not water. Why?
Answer:
Sodium is a highly reactive metal. When exposed to air, it starts to burn and forms sodium oxide. Similarly, it reacts vigorously with water. It does not react with kerosene. Therefore, to prevent its exposure to moisture. and air, it is kept in kerosene.
Question 6.
Give one effect of water and one of air on magnesium. (V.Imp.)
Answer:
Magnesium burns in air with a dazzling flame to form a white powder that is magnesium oxide. The reaction takes place between magnesium and oxygen present in atmosphere. Magnesium oxide is basic in nature as it converts red litmus paper to blue.
Question 7.
Phosphorus is kept in water. Why?
Answer:
Generally, non-metals do not react with water, but they may be very reactive in air. Such nonmetals are stored in water; phosphorus is a very reactive non-metal. It catches fire, if exposed in air. To prevent this, it is kept in water.
Question 8.
Prepare a list of some material that are good and poor conductors of electricity.
Answer:
See the list as:
(a) Good conductors of Electricity: An iron nail, a piece of aluminium foil, copper wire, etc.
(b) Poor conductors of Electricity: Peasized lump of the sulfur, a piece of coal, piece of dry wood, a piece of stone, an eraser made by rubber, the small piece of nylon rope plastic covers on screwdrivers, the rubber gloves of an electrician etc.
Question 9.
Which objects show malleability, lusture and hardness ? Name any four.
Answer:
Metals show lusture, hardness and malleability. The objects that once made by copper, iron, aluminium, silver and gold are metals.
Question 10.
(a) Name a metal that occurs in liquid state àt room temperature.
(b) Name some metals that are soft in nature and can be cut by knife.
Answer:
(a) Mercury (used in thermometers)
(b) Metals such as potassium and sodium are soft as well as they are cut by knife.
Question 11.
Compare properties of Metals and Nonmetals.
Answer:
Comparison of Metal and Non-metals:
| Metals | Non-metals |
| 1. Hard, shiny in appearance | 1. Not hard and dull in appearance |
| 2. Malleable, lustrous, ductile, sonorous | 2. Non-malleable, nonlustrous, not ductile and not sonorous |
| 3. Examples : Iron, Gold, Copper and Silver etc. | 3. Sulfur and Phosphorous |
Question 12.
Compare chemical properties of Metals and Non-metals. (M.Imp.)
Answer:
Comparison of chemical properties of Metals and Non-metals:
| Metals | Non-metals |
| 1. Generally form basic oxides with oxygen. | 1. They form acidic oxides with oxygen. |
| 2. Form oxides with the water. | 2. They do not react with water. |
| 3. Metals react with water. | 3. They do not react with water. |
Question 13.
Enlist some uses of metals in our daily life.
Answer:
Iron is used to make nails, wires and agricultural tools.
Steel is used to make cromes and the suspension bridges and utensils.
Silver and gold are used to make jewellary ornaments are made from the metal wires.
Copper is used in the electric wires. Aluminium foil is used to pack food. Zinc is used in galvanising of iron. Mercury is used in thermometers.
Question 14.
Define conductors. Write their two categories.
Answer:
Conductors: The materials which transfer heat from one point to the other of a material are conductors of heat e.g., metal spoon and a wooden spoon. Metals are good conductors of heat. Wood remains a poor conductor of heat. Hence, we use metal vessel for heating but their handles are made of wood or some other materials (which do not conduct heat at all).
Question 15.
List four uses of non-metals in everyday life.
Answer:
Phosphorous in used to make fertilizers. Oxygen is used in breathing. Carbon is key component of fats, carbohydrates and proteins. Nitrogen is necessary for plant growth. The chlorine is used in purefication of water. Moreover, iodine solution is used as an antiseptic to be applied on the wounds of a person.
Question 16.
What do you mean by rusting? How can rusting of iron be prevented ?
Answer:
Rusting is “the formation of rust on objects”. e.g., brown deposits or discolouration of an iron nail when put in moist air. It can be prevented by oiling, painting, greasing or by applying a protective layer of zinc metal on the iron. This serious problem causes loss of money that is spent on replacing prepairing iron structures damaged due to it.
Question 17.
Classify elements on the basis of their physical/chemical properties.(Imp.)
Answer:
Question 18.
Write explanatory notes on the following non-metals:
(a) Chlorine
(b) Iodine and
(c) Nitrogen
Answer:
(a) Chlorine: A non-metal, used in water purification.
(b) Iodine: A non-metal, in solution form, this may be used as an antiseptic to cure wounds of persons affected.
(c) Nitrogen: A non-metal, essential for growth of plants. Mostly useful in manufacture of chemicals and the fertilizers also. It is an essential nutrient in plant nutrition.
Question 19.
What do say about the science and society now-a-days?
Answer:
Several metals and alloys are important in daily life in our society for everyday use. Alloy (a mixture of metal and a non-metal, two or more metals etc.) and some metals are essential in modern technology at all. They form a part of an industry. Special metals are used in aerospace and atomic energy. Recycling of iron is done to minize their wastage.
Question 20.
Write note on “wonder of ancient Indian Technology”.
Answer:
Iron pillar of Delhi. It was made in about more than 1600 years ago (time of Chandragupta II). It weights upto 6000 kg with a height of eight meters. It faces open atmosphere, strong winds, intense weather conditions, heavy rainfall. There is no rusting on it now-a-days.
The World of Metals and Non metals Class 7 Long Question Answer
Question 1.
Analyse some objects in reference to malleability, lusture, non-lusture and hammering effect as well as hardness/ softness. (V. Imp.)
Answer:
The piece of copper is lustrous in appearance. It is hard and become flattened on hammering. A piece of coal is non-luctrous, soft and can be broken into pieces on hammering it. A block of wood is soft, non-lustrous but is broken into pieces on hammering. Moreover a piece of aluminium becomes flat on hammering. It is hard and show lusture also. A pea-sized lump of sulfur is soft, shows no lusture and become broken into pieces on hammering.
Question 2.
State the impact of iron on progress of the civilization in our country.
Answer:
Copper and gold are metals which are used to make objects for different purposes like utensils, jewellary, in construction also. The use of iron has significant role in our industry. Iron is used to make agricultural tools. It has significant role in our civilization.
Question 3.
Write a note on sonority of metals.
Answer:
Sonority refers “to the ringing sound production by a metal.”
Examples of it are ringing sound of ghungurus, sound of a school bell. They are due to sonority of metals. Other examples are ringing sounds produced by a metal spoon or metal coin. Dull sounds are produced by wood and coal objects.
Question 4.
What is corrosion of metals ? How it can be prevented? (Imp.)
Answer:
The corrosion refers “to a process by which the materials like metals are slowly eaten away if these are exposed to air and water.” It is discolouring of metal surface gradually by air and water. You must have seen green coating on surface if copper object, even a black coating on the surface of silver objects. It occurs when objects are kept in open atmosphere. It causes heavy losses to us. It is wasteful and troublesome process. Gold does not corrode in open air.
Question 5.
Take some amount of sulfur. Perform an experiment with it to show its burning. Analyse the result also. (V. Imp.)
Answer:
Take some amount of sulfur. Make its powder in pestle by a mortal. Take it in a deflagrating spoon. Heat this on a flame. Put it in a gas jar. Cover the gas jar by a lid tightly. Take the product formed out of jar. Analyse it. Sulfur burns in air or oxygen to form sulfur dioxide gas.
Question 6.
Describe the process of rusting and its prevention methods, with examples.
Answer:
Rusting is a chemical reaction where iron reacts with oxygen and moisture in the air, forming reddish-brown rust, which weakens iron objects like tools or bridges. It requires both air and water; iron does not rust in dry air or water alone. Prevention methods include:
a. Painting: Coating iron with paint, e.g., painting bridges to block air and moisture.
b. Oiling/Greasing: Applying oil, e.g., greasing bicyle chains to form a protective layer.
c. Galvanisation: Coating with zinc, e.g., galvanised iron buckets to prevent rust. These methods protect iron structures, saving costs on repairs and ensuring safety, as rust makes objects weak and unsafe.
The World of Metals and Non metals Class 7 Case Based Questions
1. Read the following passage carefully and answer the questions that follow:
Non-metals are essential in our daily life due to their distinct properties. They are not lustrous. They do not show malleability and ductility also. They are poor conductors of heat and electricity. Examples are oxygen, iodine, carbon, nitrogen etc.
(i) What are non-metals?
(a) They are lustrous
(b) They show malleability
(c) They exhibit ductily
(d) None of these
Answer:
(d) None of these
(ii) What are properties of non-metals?
(a) They are non-lustrous
(b) They do not show ductility
(c) They do not exhibit malleability
(d) All of these
Answer:
(d) All of these
(iii) Non-metals essential in our everyday life are:
(a) Carbon is essential to grow
(b) Oxygen is essential in breathing
(c) Nitrogen is a necessary element for growth of a plant
(d) All of these
Answer:
(d) All of these
2. Read the following passage carefully and answer the questions that follow: properties of metals, such as ductility, sonority, heat conduction, and electrical conductivity. They dipped metal and wooden spoons into hot water and checked which spoon got hotter. They also dropped a metal coin and a wooden block to hear the sound. In another experiment, they used a tester circuit to see if the materials conducted electricity.
(i) Why did the metal spoon become hotter than the wooden spoon in hot water?
(a) Metal reacts with hot water
(b) Metal is a poor conductor of heat
(c) Metal is a good conductor of heat
(d) Wooden spoons absorb water
Answer:
(c) Metal is a good conductor of heat
(ii) What property of metals allows them to produce a ringing sound when dropped?
(a) Malleability
(b) Conductivity
(c) Sonority
(d) Elasticity
Answer:
(c) Sonority
(iii) Which of the following materials would cause a bulb to glow in a tester circuit?
(a) Plastic rod
(b) Iron nail
(c) Rubber band
(d) Nylon rope
Answer:
(b) Iron nail
(iv) Why is rubber used in the handles of tools used by electricians?
(a) It is shiny and attractive
(b) It is soft and comfortable
(c) It is a poor conductor of electricity
(d) It reacts with metals
Answer:
(c) It is a poor conductor of electricity
The World of Metals and Non metals Class 7 Picture Based Questions
1. Look at the picture and answer the following questions:
(i) Which property of metal is conducting through activity?
(a) Ductility
(b) Malleability
(c) Sonority
(d) None of these
Answer:
(b) Malleability
(ii) Which property allows a metal like iron to be flattened into sheets when beaten?
(a) Ductility
(b) Brittleness
(c) Malleability
(d) Elasticity
Answer:
(c) Malleability
(iii) What are the essential conditions for rusting?
Answer:
(i) Presence of moisture (water)
(ii) Presence of air (oxygen)
The World of Metals and Non metals Extra Questions for Practice
Multiple Choice Questions (MCQs):
Question 1.
The good conductors of heat and electricity are:
(a) metals
(b) non-metals
(c) none of these
(d) all of these
Question 2.
The most malleable metals are:
(a) Gold
(b) Silver
(c) Both (a) and (b)
(d) All of these
Question 3.
The ornaments made from wires of metals are:
(a) Earrings
(b) Bangles
(c) Necklaces
(d) All of the above
Question 4.
Select the metal:
(a) Oxygen
(b) Phosphorous
(c) Sulfur
(d) Iron
Question 5.
Material which can be drawn into wires is:
(a) Gold
(b) Carbon
(c) Oxygen
(d) Coal
Very Short Answer Type Questions:
Question 1.
What are metals?
Question 2.
How can we prevent rusting of iron?
Question 3.
How plastic covering of rubber gloves protect electrician from the electric shock?
Question 4.
Name a soft metal.
Question 5.
A material can be drawn into thin wires, it is said to be a _______.
Short Answer Type Questions-I:
Question 1.
What do you mean by malleability ? Give an example of material that shows it.
Question 2.
Give on main use of iron.
Question 3.
Why phosphorous is stored in water?
Question 4.
Rusting of iron is a serious problem. Why?
Question 5.
Magnesium oxide is acidic, basic or neutral in nature. Which one is correct among these?
Question 6.
Presence of air and water are essential for formation of rust on a metal or iron nail. Make an experiment to prove it.
Question 7.
Differentiate in the sound produced by a metal spoon, a block of wood and a piece of coal.
Question 8.
Give the meaning and examples of:
(a) Malleability
(b) Ductility and
(c) Sonority
Question 9.
By an experiment show reaction of a non-metal with oxygen. Say a non-metal may be a piece of sulfur.
Question 10.
Give some uses of iron and copper.
Long Answer Type Questions:
Question 1.
Explain corrosion of metals by giving an example.
Question 2.
Show rusting of iron nail by an experiment and figures.
Question 3.
(a) Name some metals.
(b) Plastic, wood, rubber, paper are metals or non-metals. Explain briefly.
Question 4.
Why are alloys important for daily use?