Olympiad Test: Metals And Non-Metals - 2 - Class 8 MCQ

The most abundant metal on Earth is Aluminium.
Explanation:
Aluminium is the most abundant metal on Earth, accounting for approximately 8% of the Earth's crust by weight. It is widely distributed and found in various minerals such as bauxite, cryolite, and feldspar. Here are some key points to support this answer:
- Aluminium is the third most abundant element in the Earth's crust, following oxygen and silicon.
- It is a lightweight metal with a low density, making it ideal for a wide range of applications, including construction, transportation, and packaging.
- Aluminium is highly recyclable, and this contributes to its sustainability and availability in the market.
- Bauxite is the primary source of aluminium, and it is mined in several countries, including Australia, China, and Guinea.
- Aluminium is known for its corrosion resistance and high strength-to-weight ratio, making it a valuable material in various industries.
In conclusion, aluminium is the most abundant metal on Earth, and its abundance, versatility, and recyclability make it a crucial component of modern society.

- Diamond is the correct answer, as it is a form of carbon, a non-metal, that is exceptionally lustrous.
- Lustrous means having a shiny appearance, and diamond is famous for its brilliance and sparkle.
- Unlike most non-metals, which are typically dull, diamond's crystal structure allows it to reflect light brilliantly.
- Other options like sulphur, phosphorus, and oxygen are non-metals but lack the lustrous quality that characterizes diamond.

Metals are:
Metals are substances that possess certain characteristics and properties. In the context of heat and electricity conduction, metals can be described as follows:
Good conductor of heat and electricity:
- Metals are excellent conductors of heat and electricity due to the presence of free electrons in their atomic structure.
- These free electrons are delocalized and can move easily throughout the metal, allowing for efficient transfer of heat and electric current.
- The high thermal and electrical conductivity of metals makes them useful in various applications, such as electrical wiring, cooking utensils, and heat sinks.
Examples of good conductors:
- Copper (Cu): It is widely used in electrical wiring and transmission of electricity due to its high conductivity.
- Aluminum (Al): Another common metal used in electrical transmission lines, heat exchangers, and electronic components.
- Silver (Ag): Known for its highest electrical conductivity among all metals, silver is used in specialized applications like high-performance electrical contacts.
Advantages of metals as good conductors:
- Efficient transfer of heat: Metals are capable of quickly transferring heat from one point to another, making them suitable for applications where heat dissipation is important.
- Effective electricity transmission: Metals allow electric current to flow with minimal resistance, ensuring efficient transmission of electricity.
- Versatility: Metals can be easily shaped and molded into various forms, making them versatile for different applications.
Conclusion:
Metals, such as copper, aluminum, and silver, are good conductors of heat and electricity due to the presence of free electrons in their atomic structure. This property enables them to efficiently transfer heat and electric current, making them essential in various industries and applications.

Basic Oxides:
- Basic oxides are oxides that react with acids to form salts and water.
- They are also known as basic anhydrides.
- Basic oxides are typically metal oxides.

Based on the given options, let's analyze each oxide to determine if it is a basic oxide:
A. CaO:
- Calcium oxide (CaO) is a metal oxide.
- It reacts with acids to form salts and water.
- Therefore, CaO is a basic oxide.
B. CO₂:
- Carbon dioxide (CO₂) is not a metal oxide.
- It does not react with acids to form salts and water.
- Therefore, CO₂ is not a basic oxide.
C. H₂O:
- Water (H₂O) is not a metal oxide.
- It does not react with acids to form salts and water.
- Therefore, H₂O is not a basic oxide.
D. N₂O:
- Nitrous oxide (N₂O) is not a metal oxide.
- It does not react with acids to form salts and water.
- Therefore, N₂O is not a basic oxide.
Conclusion:
- Among the given options, only CaO (Calcium oxide) is a basic oxide.
- Therefore, the correct answer is A: CaO.

Explanation:
The property of metals being able to be drawn into thin wires is known as ductility. Here is a detailed explanation:
Ductility:
- Ductility is a physical property of metals that allows them to be stretched or drawn out into thin wires without breaking.
- It is the opposite of brittleness, which is the tendency of materials to break or shatter when subjected to stress.
- Ductility is an important property of metals as it allows them to be easily formed and shaped into various useful products.
- This property is due to the metallic bonds present in metals, which allow the atoms to slide past each other when a force is applied.
- The ability to be drawn into thin wires is particularly useful in the manufacturing of electrical wires, where the metal conducts the electricity and the thin wire form allows for easy installation and flexibility.
- Examples of metals that possess high ductility include gold, silver, copper, and aluminum.
Conclusion:
- The property of metals being able to be drawn into thin wires is known as ductility.
- Ductility is a desirable property for metals as it allows for easy shaping and forming of various products.
- It is particularly important in the manufacturing of electrical wires.
- Therefore, the correct answer is B: Ductility.

Explanation:
The property due to which non-metals break on hammering is called brittleness. When a material is brittle, it means that it lacks the ability to deform plastically or to sustain significant elongation before fracture. Non-metals, such as ceramics and glass, are typically brittle in nature.
Here is a detailed explanation of the property of brittleness and why non-metals break on hammering:
Brittleness:
- Brittleness is the opposite of ductility and malleability. It refers to the property of a material to break or shatter when subjected to stress, without undergoing significant deformation.
- Brittle materials have a low tolerance for plastic deformation and tend to fracture when external forces are applied.
- The fracture in brittle materials occurs along a cleavage plane, resulting in a clean break with little or no plastic deformation.
Non-Metals:
- Non-metals are a class of elements that do not possess the characteristic properties of metals, such as high electrical conductivity, malleability, and ductility.
- Non-metals include elements like carbon, oxygen, nitrogen, sulfur, and many others.
- Most non-metals have a tendency to be brittle due to their atomic structure, which consists of covalent bonds that are stronger and less flexible than metallic bonds.
Hammering:
- Hammering or striking a material with a hammer applies an external force to the material, causing it to undergo stress and deformation.
- When non-metals are subjected to hammering, their lack of ductility and malleability prevents them from undergoing plastic deformation.
- Instead, the applied stress causes the brittle material to fracture and break into smaller pieces.
Therefore, the property responsible for non-metals breaking on hammering is brittleness.

The tip of a lead pencil is made of graphite.
Graphite is a form of carbon that is commonly used in pencils due to its unique properties. Here is a detailed explanation:
Properties of Graphite:
- Graphite is a soft and brittle material.
- It has a metallic gray color and a slippery texture.
- Graphite is a good conductor of electricity.
Why is Graphite used in pencils?
- Graphite leaves a mark on paper when it is applied due to its ability to leave a layer of graphite particles on the surface.
- It has a low friction coefficient, which means it can easily glide across the paper.
- Graphite is easily erasable, making it suitable for writing and drawing purposes.
Manufacturing Process:
- The process of making a pencil tip involves mixing graphite with clay binders and water to form a paste-like mixture.
- The mixture is then extruded into thin rods and dried.
- These dried rods are then inserted into a wooden or plastic casing to form the pencil.
Conclusion:
- The tip of a lead pencil is made of graphite, which is a form of carbon.
- Graphite's unique properties make it ideal for writing and drawing purposes.
- Its ability to leave a mark on paper, low friction coefficient, and erasability are the reasons why it is commonly used in pencils.

Iron burns in air to form:

The correct answer is Fe₂O₃.

Explanation:

When iron (Fe) reacts with oxygen (O₂) in the air, it undergoes a process known as oxidation, resulting in the formation of iron(III) oxide (Fe₂O₃).

Here is a step-by-step explanation of the reaction:

1. Iron (Fe) atoms react with oxygen (O₂) molecules.


2. The iron atoms lose electrons and are oxidized to iron(III) ions (Fe³⁺).


3. The oxygen molecules gain electrons and are reduced to oxide ions (O^2-).


4. The iron(III) ions combine with the oxide ions to form iron(III) oxide (Fe₂O₃).

Therefore, the correct chemical formula for the compound formed when iron burns in air is Fe₂O₃.

To arrange the metals in increasing order of their reactivity towards water, we need to consider their position in the reactivity series. The reactivity series of metals is a list that ranks metals in order of their reactivity with water or acids.
The reactivity series is as follows:
1. Potassium
2. Sodium
3. Calcium
4. Magnesium
5. Aluminum
6. Zinc
7. Iron
8. Tin
9. Lead
10. Hydrogen
11. Copper
12. Mercury
13. Silver
14. Gold
15. Platinum
From the reactivity series, we can determine the order of reactivity of the given metals:
1. Sodium - Sodium is more reactive than all the other metals given.
2. Magnesium - Magnesium is more reactive than zinc and iron.
3. Zinc - Zinc is more reactive than iron.
4. Iron - Iron is the least reactive among the given metals.
Therefore, the correct order of increasing reactivity towards water for the given metals is:
Iron < Zinc < Magnesium < Sodium
Hence, the answer is option A: Iron 〈 Zinc 〈 Magnesium 〈 Sodium.

Explanation:
Metals and non-metals have different properties, including their malleability and ductility. Let's examine the statements:
Statement 1: Metals are malleable and ductile.
- Malleability is the ability of a material to be deformed into thin sheets without breaking. Metals are known for their malleability, which allows them to be hammered or rolled into different shapes.
- Ductility is the ability of a material to be drawn into thin wires without breaking. Metals also possess this property, which is why they are commonly used in electrical wiring.
Statement 2: Non-metals are malleable and ductile.
- This statement is incorrect. Non-metals, in general, are not malleable or ductile.
- Non-metals are usually brittle and lack the ability to be hammered into thin sheets or drawn into wires.
Conclusion:
The correct statement is Statement 1: Metals are malleable and ductile.
Therefore, the answer is A: Statement 1.

Statement 1: Metals are lustrous.

• Metals have a characteristic property of being lustrous, which means they have a shiny and reflective surface.


• This property is due to the presence of free electrons in the metallic structure, which allows the metals to reflect light and give them their characteristic shine.


• Examples of lustrous metals include gold, silver, copper, and aluminum.

Statement 2: Non-metals are not lustrous.

• Non-metals, on the other hand, generally do not have a shiny or reflective surface.


• They may appear dull, opaque, or have a matte finish.


• This is because non-metals lack the free electrons found in metals, which are responsible for reflecting light.


• Examples of non-lustrous non-metals include carbon, sulfur, nitrogen, and phosphorus.

Therefore, both statements are correct. Metals are lustrous, while non-metals are not lustrous.

Reaction between copper wire and iron (II) sulphate solution
When copper wire is dipped in iron (II) sulphate solution, a reaction occurs. However, the reaction is not between copper and iron (II) sulphate, leading to the formation of copper sulphate or iron. Instead, a different type of reaction takes place. Here's a detailed explanation:
1. Displacement reaction:
When copper wire is dipped in iron (II) sulphate solution, a displacement reaction occurs. This type of reaction involves the replacement of one element in a compound with another element. In this case, copper is more reactive than iron, so it displaces the iron in the iron (II) sulphate solution.
2. Formation of copper (II) sulphate:
As a result of the displacement reaction, copper from the copper wire replaces the iron in the iron (II) sulphate solution. This leads to the formation of copper (II) sulphate. The chemical equation for this reaction is:
Cu + FeSO4 -> CuSO4 + Fe
3. Blue coloration:
Copper (II) sulphate is a blue-colored compound. So, when copper wire is dipped in iron (II) sulphate solution, the solution turns blue. This change in color is a visual indication of the reaction taking place.
4. No formation of iron:
Since copper is more reactive than iron, it displaces the iron from the iron (II) sulphate solution. As a result, no iron is formed in this reaction.
5. No reaction with copper:
On the other hand, the copper wire itself does not undergo any significant chemical change. It remains mostly unaffected by the iron (II) sulphate solution.
In conclusion, when copper wire is dipped in iron (II) sulphate solution, copper (II) sulphate is formed through a displacement reaction. The solution turns blue due to the formation of copper (II) sulphate, while the copper wire itself remains unchanged. No iron is formed in this reaction.

The nature of the oxides formed when a metal reacts with oxygen is:
- Metal oxides are formed when metals react with oxygen. The nature of these oxides depends on the reactivity of the metal and the conditions under which the reaction occurs.
- When a metal reacts with oxygen, it undergoes oxidation and forms metal oxides.
- The nature of the metal oxides can be classified into acidic, basic, or amphoteric (showing both acidic and basic properties) based on their chemical properties.
- In general, metals on the left side of the periodic table (alkali metals and alkaline earth metals) tend to form basic oxides, while metals on the right side (transition metals) tend to form amphoteric oxides.
- Basic oxides are those that react with water to form metal hydroxides, which are alkaline in nature. They have a pH greater than 7.
- Acidic oxides, on the other hand, react with water to form acids. They have a pH less than 7.
- Neutral oxides do not react with water to form acids or bases. They are chemically inert and have a pH close to 7.
- Therefore, the correct answer is B: Basic. When a metal reacts with oxygen, it forms basic oxides.

Nature of the oxide formed when a non-metal reacts with oxygen:
When a non-metal reacts with oxygen, the nature of the oxide formed depends on the specific non-metal involved. Here are the possibilities:
1. Acidic Oxide:
- Some non-metals, such as sulfur, nitrogen, and carbon, form acidic oxides when they react with oxygen.
- These oxides react with water to form acids.
- Examples include sulfur dioxide (SO2), nitrogen dioxide (NO2), and carbon dioxide (CO2).
2. Neutral Oxide:
- Some non-metals, such as oxygen itself, form neutral oxides when they react with oxygen.
- These oxides are neither acidic nor basic.
- Examples include oxygen gas (O2) and nitrogen gas (N2).
3. Basic Oxide:
- Non-metals generally do not form basic oxides. Basic oxides are more commonly formed by metals.
- However, a few non-metals, such as selenium and tellurium, can form slightly basic oxides.
In conclusion:
The nature of the oxide formed when a non-metal reacts with oxygen can be acidic, neutral, or slightly basic, depending on the specific non-metal involved in the reaction.

Answer:
The non-metal that is commonly used as electrodes in electrolytic cells and dry cells is graphite. Graphite is a form of carbon that has a high electrical conductivity, making it suitable for use as an electrode material. It is widely used in various applications, including batteries and electrolytic cells, due to its unique properties.
Reasons why graphite is used as electrodes:
- High electrical conductivity: Graphite has a high number of delocalized electrons, which allows it to conduct electricity efficiently. This makes it ideal for use as an electrode material.
- Chemical stability: Graphite is chemically stable and resistant to corrosion, which is important for maintaining the integrity and longevity of the electrodes in electrolytic cells and dry cells.
- Low resistance: Graphite has a low resistance to the flow of electric current, reducing energy losses and ensuring efficient operation of the cells.
- Availability and cost-effectiveness: Graphite is readily available and relatively inexpensive, making it a practical choice for electrode materials in various applications.
Applications of graphite electrodes:
- Electrolytic cells: Graphite electrodes are used in electrolytic cells to facilitate chemical reactions through the conduction of electricity. These cells are commonly used in industries for processes such as electroplating, metal extraction, and electrolysis.
- Dry cells: Graphite electrodes are also used in dry cells, which are portable power sources commonly found in household batteries. The graphite electrode acts as the positive terminal and helps in the flow of electrons during the chemical reactions that generate electrical energy.
In conclusion, graphite is a non-metal that is widely used as electrodes in electrolytic cells and dry cells due to its high electrical conductivity, chemical stability, low resistance, and cost-effectiveness.

Acidic solution turns:
- A: Red litmus blue
- B: Blue litmus red
- C: Red litmus green
- D: No reaction
Explanation:
When an acidic solution is added to different indicators, it can result in various color changes. In this case, the acidic solution is causing a reaction with litmus paper.
- Litmus paper is a common indicator used to determine whether a solution is acidic or basic.
- It comes in two colors: red and blue.
- When an acidic solution is added to litmus paper, it can cause a color change, indicating its acidity.
Specifically:
- A: When an acidic solution is added to red litmus paper, it turns blue. This is because the acid reacts with the red litmus, causing it to change color.
- B: When an acidic solution is added to blue litmus paper, it turns red. This is another example of the acid reacting with the indicator and causing a color change.
- C: The statement "Red litmus green" is not correct. Acidic solutions do not turn red litmus green.
- D: The statement "No reaction" is also not correct. Acidic solutions do cause a reaction with litmus paper, resulting in a color change.
Therefore, the correct answer is B: Blue litmus red.

Basic Solution for Acid-Base Reactions:
A: Red litmus turns blue

• An acid turns blue litmus paper red. This indicates that the substance is acidic.


• Red litmus paper is red when it is neutral or basic. If it turns blue, it indicates the presence of an acid.

B: Red litmus turns green

• In the presence of a base, red litmus paper can turn green. This is a result of the alkaline nature of the substance.


• Green litmus paper is green when it is neutral or acidic. If it turns green, it indicates the presence of a base.

C: Blue litmus turns red

• A base turns blue litmus paper red. This indicates that the substance is basic.


• Blue litmus paper is blue when it is neutral or acidic. If it turns red, it indicates the presence of a base.

D: No reacting

• If no change is observed in the litmus paper, it implies that the substance is neutral.


• Neutral substances do not have any effect on litmus paper, causing no change in the color of the paper.

In summary, the basic solution turns red litmus blue, red litmus green, and blue litmus red. If no reaction occurs, it indicates that the solution is neutral.

Answer:
Metal used in thermometers and barometers:
- Mercury is the metal used in thermometers and barometers.
- It is a silvery-white heavy metal that is liquid at room temperature.
- Mercury is chosen for these instruments due to its unique properties, such as its high boiling point and low freezing point.
- It expands and contracts evenly with changes in temperature, making it ideal for measuring temperature accurately.
- In thermometers, the mercury inside the glass tube rises or falls depending on the temperature, allowing us to measure the temperature.
- In barometers, mercury is used to measure atmospheric pressure. The height of the mercury column in the barometer changes with variations in air pressure.
- The use of mercury in these instruments has become less common due to its toxicity and environmental concerns.
- Nowadays, digital thermometers and barometers have replaced mercury-based ones in many applications.

Sodium is a:
- Sodium is a silvery white and very soft metal.
- It is one of the alkali metals and belongs to the group 1 (or 1A) elements in the periodic table.
- Sodium has a low melting point and is easily cut with a knife.
- It is highly reactive and reacts vigorously with water, releasing hydrogen gas and forming sodium hydroxide.
- In its pure form, sodium is not found in nature, but it is commonly found in compounds such as sodium chloride (table salt) and sodium bicarbonate (baking soda).
- Sodium is an essential element for many biological processes and is necessary for maintaining proper fluid balance, nerve function, and muscle contraction in the human body.
- It is commonly used in various industries, including the production of chemicals, soaps, detergents, and as a coolant in nuclear reactors.
- Sodium compounds are also used in food preservation, water treatment, and as a flavor enhancer in processed foods.
- However, excessive sodium intake can be harmful to health and is associated with high blood pressure and an increased risk of cardiovascular diseases.

Non Metal Hardness:
The hardest substance known among non-metals is Diamond.
Explanation:
Diamond is a form of carbon and is considered the hardest known naturally occurring substance. Here is a detailed explanation:
Diamond Structure:
- Diamond is made up of carbon atoms arranged in a crystal lattice structure.
- Each carbon atom is bonded to four other carbon atoms in a tetrahedral arrangement, creating a strong and rigid network.
Hardness Scale:
- Hardness is measured using the Mohs scale, which ranks minerals based on their ability to scratch other minerals.
- The Mohs scale ranges from 1 to 10, with 10 being the hardest.
- Diamond has a hardness of 10 on the Mohs scale, making it the hardest known substance.
Properties of Diamond:
- Diamond has exceptional hardness due to its strong carbon-carbon bonds.
- It is highly resistant to scratching, making it suitable for industrial applications such as cutting, grinding, and polishing.
- Its hardness also gives diamond its renowned brilliance and ability to refract light.
Comparison to Other Options:
- Graphite: Graphite is a form of carbon as well, but it has a layered structure that makes it relatively soft and slippery. It has a Mohs hardness of around 1-2.
- Phosphorus: Phosphorus is a non-metal, but it is not known for its hardness. It has a Mohs hardness of around 2.5.
- Hydrogen: Hydrogen is a gas and does not possess a definitive hardness value.
Therefore, the correct answer is C: Diamond as it is the hardest known substance among non-metals.