Class 10 Science Metals and Non-Metals Chapter All Notes

 

1.   Introduction to metals and non-metals

Metals and non-metals are two groups of elements that have distinct physical and chemical properties. Metals are typically shiny, conductive, and have a high density. They are typically found on the left side of the periodic table and are known for their ability to lose electrons, making them good conductors of electricity.

On the other hand, non-metals are typically dull, poor conductors of heat and electricity, and have a lower density. They are typically found on the right side of the periodic table and are known for their ability to gain electrons, making them poor conductors of electricity.

Some elements, such as carbon, silicon, and germanium, are considered to be semi-metals as they exhibit properties of both metals and non-metals.

The properties of metals and non-metals can be used to classify elements and predict their chemical behavior.

 

Physical and chemical properties of metals and non-metals

Physical Properties of Metals:

• High density
• Good conductors of heat and electricity
• Malleable and ductile
• Shiny appearance when freshly polished
• Solid at room temperature (with the exception of mercury)
• Hard and strong
• Have a metallic luster
• Usually have a high melting and boiling point

Chemical Properties of Metals:

• Tend to lose electrons in chemical reactions
• Form positive ions (cations)
• Tend to react with non-metals to form compounds
• Generally react with acids to produce hydrogen gas
• Can be extracted from ores through processes such as smelting and electrolysis

Physical Properties of Non-Metals:

• Low density
• Poor conductors of heat and electricity
• Not malleable or ductile
• Generally dull in appearance
• Can be in solid, liquid, or gas state at room temperature
• Soft and brittle
• Usually have a low melting and boiling point

Chemical Properties of Non-Metals:

• Tend to gain electrons in chemical reactions
• Form negative ions (anions)
• Tend to react with metals to form compounds
• Generally do not react with acids
• Can be obtained through processes such as distillation or sublimation.

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Characteristics of metals and non-metals

Characteristics of Metals:

• High melting and boiling point
• Good conductors of heat and electricity
• Malleable and ductile
• Shiny appearance when freshly polished
• Solid at room temperature (with the exception of mercury)
• Hard and strong
• Have a metallic luster
• Tend to lose electrons in chemical reactions
• Form positive ions (cations)
• Tend to react with non-metals to form compounds
• Generally react with acids to produce hydrogen gas

Characteristics of Non-Metals:

• Low melting and boiling point
• Poor conductors of heat and electricity
• Not malleable or ductile
• Generally dull in appearance
• Can be in solid, liquid, or gas state at room temperature
• Soft and brittle
• Tend to gain electrons in chemical reactions
• Form negative ions (anions)
• Tend to react with metals to form compounds
• Generally do not react with acids
• Can be obtained through processes such as distillation or sublimation.

Characteristics of semi-metals:

• They have intermediate characteristics between metals and non-metals
• They are typically dull in appearance
• They are poor conductors of heat and electricity
• They are brittle and not malleable or ductile
• They can be in solid state at room temperature
• They have a low melting and boiling point
• They tend to gain or lose electrons depending on the chemical compound they form
• They are typically found between the metals and non-metals on the periodic table.

 

Reactivity of metals and non-metals

Reactivity of Metals:

Metals tend to be highly reactive due to their tendency to lose electrons. They are reactive with non-metals, particularly with oxygen, to form compounds called oxides. For example, when iron is exposed to air, it reacts with oxygen to form iron oxide (rust). Metals also react with acids, releasing hydrogen gas. For example, when zinc is placed in hydrochloric acid, it reacts to form zinc chloride and hydrogen gas.

Metals can be found in nature in the form of compounds called ores. To obtain the pure metal, the ore must be processed through methods such as smelting or electrolysis. These methods involve heating the ore with a reducing agent, which causes the metal to lose electrons and become pure.

Reactivity of Non-Metals:

Non-metals tend to be less reactive than metals due to their tendency to gain electrons. They can react with other non-metals to form compounds, but they do not react with metals. For example, carbon and oxygen can react to form carbon dioxide. Non-metals also do not react with acids and instead, they tend to react with bases to form salts.

Non-metals can be obtained from natural sources through methods such as distillation or sublimation. These methods involve heating the substance to a high temperature and capturing the gas or solid that is released.

In general, non-metals reactivity is less than metals, but some non-metals like sulfur and chlorine are more reactive than many metals.

 

 

Extraction of metals

The extraction of metals involves the process of obtaining pure metal from its ore. The process of extraction can vary depending on the metal and the type of ore it is found in. The following are some common methods used for the extraction of metals:

1. Smelting: This process involves heating the ore with a reducing agent, such as coke or charcoal. The reducing agent causes the metal to lose electrons and become pure. This method is used for extracting metals such as iron, zinc, and copper.
2. Electrolysis: This process involves passing an electric current through a solution containing dissolved metal ions. The metal ions are then reduced to the pure metal at the cathode and the impurities are left behind at the anode. This method is used for extracting metals such as aluminum and magnesium.
3. Leaching: This process involves dissolving the metal ions in a solution, usually an acid or a base, and then separating the solution from the remaining solid material. This method is used for extracting metals such as gold and silver.
4. Bioleaching: This process involves using microorganisms to extract metals from ores. This method is used for extracting metals such as copper and nickel.
5. Carbon reduction: This process involves using carbon to reduce the metal ions to the pure metal. This method is used for extracting metals such as gold and silver.

All these methods are used based on the type of metal, the concentration of metal in the ore, and the availability of the reducing agents or reagents.

 

 

Uses of metals and non-metals

Uses of Metals:

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• Iron and steel are used in construction and manufacturing of buildings, bridges, and cars
• Copper is used in electrical wiring and plumbing
• Aluminum is used in airplanes, cans, and cooking utensils
• Gold and silver are used in jewelry, coins, and electronic devices
• Platinum is used in catalytic converters, jewelry, and electronic devices
• Zinc is used in galvanizing (coating steel to prevent rust) and in the production of zinc oxide (a common sunblock ingredient)
• Tin is used in tin cans, tin plating, and in the production of bronze
• Lead is used in batteries and as a radiation shield.

Uses of Non-metals:

• Carbon is used in the production of steel, graphite, and diamond
• Oxygen is used in respiration and combustion
• Nitrogen is used in fertilizers and in the production of ammonia for industrial uses
• Hydrogen is used in the production of fuel, fertilizers, and in rocket propulsion
• Chlorine is used in water treatment and in the production of PVC (polyvinyl chloride)
• Sulfur is used in fertilizers, in the production of sulfuric acid, and as a fungicide
• Phosphorus is used in fertilizers and in the production of phosphoric acid
• Iodine is used in medicine, as a disinfectant, and in photography
• Fluorine is used in toothpaste, water treatment, and in the production of Teflon.

In general, metals have high melting and boiling points, good conductors of heat and electricity, and have a metallic luster. They are widely used in construction, manufacturing, transportation, and electronic industries. On the other hand, non-metals are usually poor conductors of heat and electricity, they have low melting and boiling points and they are mostly gases or brittle solids. They are used in agriculture, medicine, and industrial processes.

 

Alloys and their uses

An alloy is a mixture of two or more elements, at least one of which is a metal. Alloys are created to enhance the properties of the base metals, such as strength, ductility, toughness, and resistance to corrosion or wear. Some common alloys and their uses include:

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• Steel: an alloy of iron and carbon, used in construction, tools, and vehicles.
• Brass: an alloy of copper and zinc, used in plumbing fixtures, musical instruments, and decorative items.
• Bronze: an alloy of copper and tin, used in sculpture, coins, and bearings.
• Aluminum: an alloy of aluminum and small amounts of other metals such as copper, magnesium, and silicon, used in packaging, transportation, and construction.
• Gold: an alloy of gold and other metals such as copper, silver or palladium, used in jewelry and electronic components.
• Stainless Steel: an alloy of iron, chromium, and nickel, used in cutlery, appliances, and medical equipment.

Alloys can be designed to have specific properties for different application, such as aerospace, automotive, construction, electronics, and medical industry, making them incredibly versatile and useful materials.

 

 

Environmental impacts of metal extraction and usage

The extraction and usage of metals can have significant environmental impacts, both during the mining and processing stages, as well as during the use and disposal of metal products. Some of the main environmental impacts include:

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• Deforestation and habitat destruction: mining operations often require the removal of large areas of forest, destroying habitats for plants and animals.
• Water pollution: mining and processing of metals can release toxins and heavy metals into nearby water sources, which can be harmful to aquatic life and can also contaminate drinking water.
• Air pollution: mining and processing operations can release particulate matter, sulfur dioxide, and other pollutants into the air, which can be harmful to human health and the environment.
• Land degradation: mining can result in erosion and the formation of sinkholes, and can also leave behind land that is contaminated and unable to support vegetation.
• Resource depletion: mining and processing metals can require large amounts of energy and water, leading to depletion of natural resources.
• Greenhouse gas emissions: mining and processing of metals can generate greenhouse gas emissions, which contribute to climate change.
• Waste generation: mining and processing operations can generate large amounts of waste, including tailings and slag, which can be difficult and costly to manage.
• Health hazards: mining and processing of metals can expose workers to dangerous levels of toxic substances, as well as dust and noise.

The use and disposal of metal products can also have environmental impacts, such as energy consumption during use, and pollution during disposal. Some metals are also toxic and can harm the ecosystem when they're released into the environment.

Overall, the environmental impacts of metal extraction and usage can be significant and wide-ranging. Therefore, sustainable and responsible mining and processing practices are important to minimize these impacts and ensure the protection of the environment.

 

Summary and review questions.

A summary of metals and non-metals would be:

Metals are elements that are typically solid at room temperature, have a metallic luster, are good conductors of heat and electricity, and can be shaped by hammering or rolling. Examples of metals include gold, copper, iron, and aluminum.

Non-metals are elements that are typically gases or brittle solids at room temperature, do not have a metallic luster, are poor conductors of heat and electricity, and cannot be shaped by hammering or rolling. Examples of non-metals include carbon, sulfur, nitrogen, and chlorine.

 

To Summarize:

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• Metals are typically shiny, dense, and good conductors of heat and electricity.
• Non-metals are typically dull in appearance, less dense, and poor conductors of heat and electricity.
• Both metals and non-metals can be found in the Earth's crust and are extracted through mining and refining processes.
• Both metals and non-metals have a wide range of applications in different industries.

Review Questions:

1. What are the physical properties of metals?
2. What are the physical properties of non-metals?
3. How are metals and non-metals extracted from the Earth's crust?
4. What are some common examples of metals and non-metals?
5. In which industries are metals and non-metals used?

6.    What are the characteristics of metals?

7.    Give examples of common metals

8.    What are the characteristics of non-metals?

9.    Give examples of common non-metals

10. How do the properties of metals and non-metals differ?

11. Can a metal be a good conductor of electricity and a poor conductor of heat?

12. How do the uses of metals and non-metals differ?

13. How do the environmental impacts of mining and using metals differ from those of non-metals?