Students rely on Class 7 Science Extra Questions and Class 7th Curiosity Chapter 4 The World of Metals and Non metals Important Extra Question Answer to improve their grades.
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.
What is malleability?
Answer:
The property of metals to be beaten (hammered) into very thin sheets without breaking.
Question 2.
What is ductility?
Answer:
The property of materials (metals) by which they can be drawn into wires.
Question 3.
Give five examples of metals.
Answer:
Copper, aluminium, iron, gold, silver.
Question 4.
What is sonority?
Answer:
The property of ringing sound produced by metals is called sonority.
Question 5.
Are non-metals sonorous?
Answer:
No. Non-metals are not sonorous; they produce a dull sound.
Question 6.
Which elements are good conductors of heat and electricity?
Answer:
Metals such as aluminium, iron and copper are good conductors of heat and electricity.
Question 7.
Name two categories of elements
Answer:
Metals and non-metals.
Question 8.
What is the number of elements known presently?
Answer:
118 elements.
Question 9.
Name the metal used in atomic energy.
Answer:
Zirconium.
Question 10.
Which non-metal is the building block of all life forms?
Answer:
Carbon. It is the key component of proteins, fats and carbohydrates, which are necessary for growth.
The World of Metals and Non metals Class 7 Short Question Answer
Question 1.
A block of wood is neither malleable nor brittle. Give reasons.
Answer:
A block of wood is not an element (metal or non-metal). It cannot be beaten into sheets and/or drawn into wires.
Question 2.
What is the nature of oxides of metals?
Answer:
On burning, metals react with oxygen to produce oxides which are generally basic in nature.
Question 3.
Name 5 properties of metals.
Answer:
Malleability, ductility, sonority, good conductors of heat and electricity, lustrous.
Question 4.
Why metals are used for making bells?
Answer:
Metals are sonorous and produce a ringing sound when hit with some solid object, so they are used for making bells.
Question 5.
What is corrosion of metals?
Answer:
The process of slow conversion of metals into their undesirable compounds (usually oxides) by reaction with moisture and other gases present in the atmosphere is called corrosion of metals.
Question 6.
How metal oxides differ from non-metal oxides?
Answer:
| Metal oxides | Non metallic oxides |
| 1. Basic compounds | 1. Acidic compounds |
| 2. React with water: Forming basic solution | 2. React with water: Forming acidic solutions. |
| 3. Physical property:
Solid, dense, 86 have high melting points |
3. Physical property:
gases or low-boiling liquids. |
| 4. Magnesium oxide | 4. Sulfur oxide. |
The World of Metals and Non metals Class 7 Long Question Answer
Question 1.
Distinguish between metals and non-metals on the basis of malleability, ductility, conduction of heat & electricity, appearance, hardness.
Answer:
| Property | Metals | Non-metals |
| 1. Malleability | Metals are malleable (can be beaten into sheets). | Non-metals are not malleable. |
| 2. Ductility | Metals are ductile (can be drawn into wires). | Non-metals are not ductile. |
| 3. Conduction of heat & electricity | Metals are good conductors of heat and electricity. | Non-metals are poor conductors of heat and electricity. |
| 4. Appearance | Metals are lustrous (shiny). | Non-metals are dull. |
| 5. Hardness | Metals are hard (except sodium and potassium; mercury is liquid at room temperature). | Non-metals are generally soft except for carbon (diamond is the hardest of natural substances). They are usually solid or gaseous at room temperature except for bromine which is liquid at room temperature. |
Question 2.
Give 5 properties of metals. Name 5 metals.
Answer:
Metals are malleable, ductile, good conductors of heat and electricity, sonorous; metal oxides are basic in nature.
Metals: Copper, Iron, Aluminium, Gold, Sodium.
Question 3.
Give 5 properties of non-metals. Name 5 non-metals.
Answer:
Non-metals are not malleable and ductile. They are poor conductors of heat and electricity. They are not sonorous. Non-metal oxides are acidic in nature. Solution of a non-metal oxide with water turns blue litmus red.
Non-metals : Carbon, sulfur, phos-phorous, nitrogen, oxygen.
The World of Metals and Non metals Class 7 Case Based Questions
I. Copper is widely used to make electric wires, electric motors and many other electric appliances. It is also used to make cooking utensils and water boilers in factories. It forms many alloys such as brass, bronze, etc.
Answer the following questions:
Question 1.
Why cooking utensils are made of copper?
Answer:
Material used for making cooking utensils should be a good conductor of heat that can transfer heat from one point to another of the material. It should also not melt easily on heating for cooking. Copper has these properties and therefore is used for making cookware.
Question 2.
Name two alloys of copper. What are their uses?
Answer:
Brass and bronze. Brass is used for making water-taps, utensils and bronze for statues.
Question 3.
Which is more ancient – copper or iron? Which of the two occurs naturally in nature?
Answer:
Copper is more ancient- its history dates back to about 8000 – 5000 BCE. Compared to iron which is 1200 BCE old. Copper occurs naturally in native form while iron occurs in the form of ores.
II. There is no sharp line dividin’g metals and non-metals. There are certain elements which exhibit properties of metals as well as non-metals; these are called metalloids.
Some examples of metalloids are: Silicon, Germanium, Arsenic, Antimony and Tellurium.
Answer the following questions:
Question 1.
What are metalloids?
Answer:
Certain elements which exhibit properties of metals as well as > non-metals are called metalloids.
Question 2.
Name 5 metalloids.
Answer:
Silicon, Germanium, Arsenic, Antimony, Tellurium.
Question 3.
What are alloys? How do alloys differ from metalloids?
Answer:
Alloys are mixtures of two or more metals, or a metal and a non-metal (steel). They are important for daily use as utensils and tools.
| Alloys | Metalloids |
| 1. Alloys are mixtures of two or more metals, or a metal and a non-metal. | 1. Metalloids are elements which exhibit properties of both metals and non-metals because there is no sharp line dividing metals and non-metals. |
| 2. Examples: Brass, Bronze, Steel. | Examples: Silicon, Germanium, Arsenic. |
The World of Metals and Non metals Extra Questions for Practice
Very Short Answer Type Questions
Question 1.
Which non-metal is used in fertilizers?
Question 2.
Name two metals used for making electric wire.
Question 3.
Name a non-metal which is very hard.
Question 4.
Name the property of metals by virtue of which they can be hammered into thin sheets.
Question 5.
Name the metal used for galvanisation of iron to protect it from rusting.
Question 6.
Name the non-metal essential for breathing.
Question 7.
Which metal is used in aerospace?
Question 8.
Which metal has contributed significantly to the progress of civilisation in India?
Question 9.
What is rusting?
Short Answer Type Questions
Question 1.
Give two properties shown by metals that are generally not shown by non-metals.
Question 2.
Why are aluminium foils used to wrap food items?
Question 3.
Metallic pans used for cooking have plastic or wooden handles. Give reason.
Question 4.
Which of the following elements is/are malleable— Carbon, Copper, Silver, Gold?
Long Answer Type Questions
Question 1.
Classify the following elements into metals and non-metals on the basis of their properties: Oxygen, Nitrogen, Copper, Chlorine, Carbon, Gold, Sodium.
Question 2.
Give two uses of metals and two uses of non-metals in daily life.
Question 3.
How do metal oxides differ from non-metal oxides?
Case-Based Questions:
Question 1.
All metals are good conductors of heat and electricity. Silver is the best conductor of heat. The poorest conductor among the metals is lead. Copper and aluminium are also good conductors of heat; that is why cooking utensils and water boilers are generally made of copper and aluminium.
(a) Which is the best conductor of heat?
(b) What is conduction?
(c) Which non-metal is a good conductor of electricity and is used in making electrodes?
Question 2.
Aluminium, when exposed to air, reacts with oxygen and gets covered with a thin, sticky layer of aluminium oxide which protects the metal from further corrosion. Hence aluminium can be used to make utensils for cooking inspite of being highly reactive.
(a) Is aluminium a metal or non-metal? Give reasons to support your answer.
(b) Why Aluminium is used to make cooking utensils. Give reasons.
(c) Give uses of aluminium on the basis of its properties.
(d) How is the use of aluminium sustainable for future generations in India?
Multiple Choice Questions (MCQs)
Choose the correct option in the following questions:
Question 1.
Which of the following can be beaten into thin sheets?
(a) Zinc
(b) Phosphorus
(c) Sulfur
(d) Oxygen
Question 2.
Which of the following statements is correct?
(a) All metals are ductile
(b) All non-metals are ductile
(c) Generally, metals are ductile
(d) Some non-metals are ductile
Question 3.
Which of the following oxides is acidic in nature?
(a) Sodium oxide
(b) Iron oxide
(c) Calcium oxide
(d) Sulfur dioxide
Question 4.
Which of the following property is generally not shown by metals? .
(a) Ductility
(b) Sonorous in nature
(c) Dullness
(d) Electric conduction
Question 5.
An element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following
(a) Magnesium
(b) Sodium
(c) Phosphorus
(d) Calcium
Assertion-Reason Questions
Directions: Each of the questions (i) and (ii) contain two statements – first ‘Assertion’ and second ‘Reason’. Select the correct answer to these questions from the codes (a), (b), (c) or (d) as given below:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true and Reason is NOT the correct explanation of Assertion.
(c) Assertion is true and Reason is false.
(d) Assertion is false and Reason is true.
(i) Assertion (A): Most of the metals are hard.
Reason (R): Sodium and potassium can be easily cut with a knife.
(ii) Assertion (A): Aluminium foil is used for wrapping food items; it is formed by beating it with a hammer.
Reason (R): Aluminium is a metal and is malleable.
Fill in the blanks
(i) Rusting of iron does not occur in ________
(ii) Solution of metal oxide with water is ________ in nature.
(iii) Objects like ________ and aluminium are lustrous.
(iv) Non-metals are generally ________ conductors of heat and electricity.
(v) An ________ is a substance that cannot be broken down into simpler substances.
True or False
State whether True or False answer with reason
(i) Wood, plastic and rubber are elements.
(ii) The oxides of non-metals are acidic in nature.
(in) Phosphorus is stored in water as it is very soft.
(iv) Only alloys are used to make utensils and tools.
Match the following:
Question 1.
Match the following items given in Column A with that in Column B:
| Column A | Column B |
| 1. A reactive non-metal | (a) Iron, Aluminium |
| 2. A reactive metal | (b) Basic in nature |
| 3. Solution of metal oxide | (c) Phosphorus |
| 4. Recycling of metals in India | (d) Sodium |