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Class 10 Science Unit 3: Metals and Non-metals

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The chapter Metals and Non-metals is one of the most important and practical chapters in Class 10 Science. It explains the properties of metals and non-metals, how they differ from each other, how they react with oxygen, water, acids, and salt solutions, and why some substances are used in electrical wires while others are used in chemicals, medicines, or fuel. This chapter also introduces the reactivity series, corrosion, extraction of metals, and the uses of important materials such as alloys. The ideas in this chapter are not limited to chemistry textbooks; they appear in daily life, industry, construction, electronics, and environmental science.

A student often first learns that metals are generally shiny, hard, and good conductors, while non-metals are usually dull, brittle, and poor conductors. But the real chemistry of this chapter goes deeper than simple definitions. We must understand why these properties exist, how metals form positive ions, why non-metals tend to gain or share electrons, and how the arrangement of atoms affects their behaviour. Once these ideas become clear, the reactions and properties described in the chapter become much easier to remember.

This chapter is highly scoring in exams because it includes definitions, comparisons, chemical equations, laboratory observations, and application-based questions. It also lays the foundation for later study of electrolysis, extraction of metals, corrosion prevention, and the chemistry of alloys. A careful understanding of this chapter helps students connect chemistry with the physical world around them.

What Are Metals?

Metals are elements that generally have a shiny appearance, are hard and strong, can be beaten into sheets, drawn into wires, and conduct heat and electricity well. They are usually solids at room temperature, except for mercury, which is liquid. Common examples include iron, copper, aluminium, gold, silver, zinc, and magnesium.

The behaviour of metals is closely related to their atomic structure. Metal atoms usually have one, two, or three electrons in their outermost shell. These electrons are loosely held and can be lost easily. When a metal atom loses electrons, it becomes a positively charged ion, or cation. This ability to lose electrons explains many of the chemical properties of metals.

Metals are widely used because of their strength, conductivity, and ability to be shaped. Iron is used in construction, copper in electrical wiring, aluminium in utensils and aircraft, and gold and silver in ornaments. Their importance in modern life is enormous.

What Are Non-metals?

Non-metals are elements that generally do not show the properties of metals. They are usually dull, brittle if solid, poor conductors of heat and electricity, and do not produce a metallic sound. Some non-metals exist as solids, some as liquids, and many as gases at room temperature. Examples include carbon, sulphur, phosphorus, oxygen, nitrogen, chlorine, and bromine.

Non-metals usually have four, five, six, or seven electrons in their outermost shell. They tend to gain, share, or accept electrons rather than lose them easily. When a non-metal gains electrons, it forms a negatively charged ion, or anion. This tendency is one of the main reasons behind the chemical behaviour of non-metals.

Non-metals are essential for life and industry. Oxygen is required for respiration, nitrogen is a major part of the atmosphere, carbon is the basis of organic compounds, and chlorine is used for water purification. So non-metals are not less important than metals; they simply behave differently.

Physical Properties of Metals

Metals show several common physical properties. These properties help us identify them and understand their uses.

1. Lustre

Metals have a shiny surface called lustre. Freshly cut metal surfaces reflect light well. This shine makes metals useful in jewellery and decoration. However, some metals lose their shine due to oxidation or corrosion over time.

2. Malleability

Metals can be beaten into thin sheets without breaking. This property is called malleability. Aluminium foil is a common example. Gold and silver are among the most malleable metals. Malleability is possible because metal atoms can slide over one another while the metallic bond still holds the structure together.

3. Ductility

Metals can be drawn into thin wires. This is called ductility. Copper and aluminium are widely used in electrical wiring because they are ductile and good conductors. Ductility is another property linked to the arrangement of atoms in metals.

4. Conductivity

Metals are generally good conductors of heat and electricity. This is because their electrons are free to move through the structure. When a voltage is applied, these free electrons carry electric current. That is why metals are used in wires, circuits, utensils, and heat-transferring objects.

5. Sonority

Metals produce a ringing sound when struck. This property is called sonority. Because of this, metal objects such as bells and cymbals make a clear sound.

6. Hardness and Strength

Most metals are hard and strong, though some like sodium and potassium are soft enough to be cut with a knife. Hardness and strength make metals useful in tools, machines, and construction. However, different metals vary in their hardness, melting point, and density.

Physical Properties of Non-metals

Non-metals generally show properties opposite to metals, but there are exceptions. This is important because chemistry does not work only through fixed rules; it also includes exceptions that must be remembered carefully.

1. Dull Appearance

Many non-metals are dull and do not shine like metals. Graphite is an exception because it has a metallic-looking surface, but most non-metals are not lustrous.

2. Brittleness

Solid non-metals are usually brittle. They break or crumble when hammered. They are not malleable or ductile. This is one reason why they are not used for structural purposes in the same way as metals.

3. Poor Conductivity

Non-metals are generally poor conductors of heat and electricity. Graphite is a notable exception because it conducts electricity due to the presence of free electrons in its structure.

4. No Sonority

Non-metals do not produce a ringing sound when struck. They are non-sonorous.

5. State at Room Temperature

Many non-metals are gases at room temperature, such as oxygen and nitrogen. Some are solids like sulphur and carbon, and bromine is a liquid. This variety makes non-metals interesting and important in chemical study.

Chemical Properties of Metals

The chapter discusses several chemical reactions of metals. These reactions help us understand how reactive a metal is and how it behaves in different environments.

1. Reaction of Metals with Oxygen

Metals react with oxygen to form metal oxides. Most metal oxides are basic in nature, although some metals form amphoteric oxides. The nature of the oxide gives an important clue about the chemical character of the metal.

Example:

2Mg + O₂ → 2MgO

Magnesium burns in air with a bright white flame and forms magnesium oxide. The oxide formed is basic.

Another example is iron. Iron reacts slowly with oxygen, especially in moist conditions, forming rust. Copper forms a green coating on prolonged exposure to air and moisture. Different metals react at different rates depending on reactivity.

Amphoteric Oxides

Some metal oxides show both acidic and basic behaviour. These are called amphoteric oxides. Aluminium oxide and zinc oxide are important examples. They react with acids as well as bases.

Example:

ZnO + 2HCl → ZnCl₂ + H₂O

ZnO + 2NaOH → Na₂ZnO₂ + H₂O

2. Reaction of Metals with Water

Some metals react with cold water, some react with hot water, and some react only with steam, while some do not react at all. This difference helps us rank metals in order of reactivity.

Sodium and potassium react violently with cold water. Calcium reacts less violently. Magnesium reacts slowly with hot water and more readily with steam. Aluminium, zinc, and iron react with steam. Copper, silver, and gold do not react with water.

Example:

2Na + 2H₂O → 2NaOH + H₂

These reactions usually produce metal hydroxide and hydrogen gas. The reaction may be highly exothermic in case of very reactive metals.

3. Reaction of Metals with Acids

Many metals react with dilute acids to produce salt and hydrogen gas. The gas is identified by the pop sound test. However, not all metals react with dilute acids. Very unreactive metals like copper, silver, gold, and platinum do not react with dilute hydrochloric acid or dilute sulphuric acid.

Example:

Zn + 2HCl → ZnCl₂ + H₂

The reactivity of the metal determines whether hydrogen is displaced from the acid. More reactive metals displace hydrogen more easily.

4. Reaction of Metals with Salt Solutions

A more reactive metal can displace a less reactive metal from its salt solution. This is one of the most important ideas in the chapter and leads to the reactivity series. The relative activity of metals is tested by observing whether displacement occurs.

Example:

Fe + CuSO₄ → FeSO₄ + Cu

Iron is more reactive than copper, so it displaces copper from copper sulphate solution. The blue solution turns green because ferrous sulphate is formed.

Reactivity Series

The reactivity series is a list of metals arranged in decreasing order of reactivity. It helps predict displacement reactions, corrosion tendency, and extraction methods.

The common order includes potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, hydrogen, copper, mercury, silver, gold, and platinum. Metals at the top are highly reactive, and those at the bottom are least reactive.

This series is very useful because it explains why some metals react strongly with water or acids while others remain unchanged. It also helps chemists choose suitable methods for extracting metals from ores.

Chemical Properties of Non-metals

Non-metals also react with oxygen, water, and some other substances, but their reactions are different from metals.

1. Reaction with Oxygen

Non-metals usually form acidic oxides when they react with oxygen. These oxides dissolve in water to produce acids.

Example:

C + O₂ → CO₂

Carbon dioxide is an acidic oxide. Sulphur dioxide is another important example.

2. Reaction with Water

Most non-metals do not react with water, which is another difference from many metals. This property also shows their low reactivity with water under normal conditions.

3. Reaction with Acids

Non-metals generally do not react with dilute acids to release hydrogen gas. This is because they are not able to displace hydrogen from acids in the way reactive metals do.

4. Reaction with Bases

Some non-metals, especially non-metal oxides, can react with bases. Since many non-metal oxides are acidic, they react with basic substances to form salt and water.

Ionic Bonding

One of the major ideas in this chapter is the formation of ionic compounds. When a metal reacts with a non-metal, electrons are transferred from the metal to the non-metal. The metal becomes a positive ion and the non-metal becomes a negative ion. The opposite charges attract, forming an ionic bond.

Example: Sodium reacts with chlorine to form sodium chloride.

2Na + Cl₂ → 2NaCl

Sodium loses one electron and chlorine gains one electron. This electron transfer creates stable ions.

Ionic compounds have high melting and boiling points because the attraction between ions is strong. They conduct electricity in molten state or aqueous solution because ions can move freely. They are generally soluble in water and hard in nature.

Properties of Ionic Compounds

• High melting and boiling points
• Hard and brittle nature
• Conduct electricity in molten or dissolved state
• Usually soluble in water
• Form crystalline structures

These properties arise because of strong electrostatic attraction between positive and negative ions. Understanding ionic bonding helps explain many reactions of metals and non-metals.

Corrosion

Corrosion is the gradual destruction of a metal by the action of air, water, or chemicals. Rusting of iron is the most familiar example. When iron reacts with oxygen and moisture, hydrated iron oxide is formed. This rust is flaky and weak, so it damages the object over time.

Corrosion is not limited to iron. Copper develops a green coating, silver becomes black due to tarnishing, and aluminium forms a thin oxide layer that protects it from further damage. Corrosion is a major industrial problem because it weakens bridges, pipes, vehicles, and machines.

Corrosion can be prevented by painting, oiling, greasing, galvanizing, alloying, coating with plastic, or keeping metals dry. Galvanizing means coating iron with zinc to prevent rusting. Alloying is often more effective because it improves strength and resistance.

Alloys

An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. Alloys are made to improve the properties of metals. For example, steel is an alloy of iron and carbon, brass is an alloy of copper and zinc, and bronze is an alloy of copper and tin.

Alloys are often stronger, more durable, and more resistant to corrosion than pure metals. They are widely used in construction, tools, machinery, utensils, electrical goods, and ornaments. The concept of alloys is very important because pure metals are not always suitable for practical use.

Extraction of Metals

Metals are not usually found in pure form in nature. They are found in ores, which are naturally occurring minerals from which metals can be extracted profitably. The method of extraction depends on the reactivity of the metal.

Very reactive metals are extracted by electrolytic methods. Less reactive metals may be extracted by heating, roasting, reduction with carbon, or displacement. Unreactive metals such as gold and silver may occur in native form or may require easier methods of extraction.

The process of extracting a metal from its ore usually involves several stages: concentration of the ore, conversion to oxide, reduction to metal, and refining or purification. Even though this chapter introduces the topic only briefly, students should understand the idea that extraction depends on reactivity.

Ores and Minerals

Minerals are naturally occurring substances found in the earth’s crust. Ores are those minerals from which metals can be extracted economically. Not every mineral is an ore, but every ore is a mineral.

Important Uses of Metals and Non-metals

Metals are used in construction, transport, electrical wiring, machinery, cookware, jewellery, and tools. Aluminium is used in aircraft and foils, copper in wires, iron in buildings and bridges, and gold and silver in ornaments.

Non-metals are used in fertilizers, medicines, fuel, disinfection, respiration, and industrial chemicals. Oxygen is needed for life, nitrogen is important for fertilizers, chlorine is used for purification, sulphur is used in chemicals, and carbon forms the basis of most living compounds.

Important Definitions

• Metal: An element that is generally lustrous, malleable, ductile, sonorous, and a good conductor.
• Non-metal: An element that generally lacks metallic properties and is usually brittle and a poor conductor.
• Ionic bond: The bond formed by electrostatic attraction between oppositely charged ions.
• Reactivity series: Arrangement of metals in decreasing order of reactivity.
• Corrosion: Slow deterioration of metals due to chemical action.
• Alloy: A homogeneous mixture of metals or a metal with another element.
• Ores: Minerals from which metals can be extracted economically.
• Galvanization: Coating iron or steel with zinc to prevent rusting.
• Amphoteric oxide: An oxide that reacts with both acids and bases.

Class 10 Science Unit 3 Notes PDF

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Exam-Oriented Revision Points

Students should remember the physical properties of metals and non-metals, the chemical reactions of metals with oxygen, water, acids, and salt solutions, the reactivity series, and the properties of ionic compounds. They should also know how corrosion happens and how it can be prevented, along with the uses of alloys.

In written answers, it is important to mention examples and equations clearly. For reaction-based questions, write the equation and then explain the observation. For comparison questions, present the differences between metals and non-metals in a neat table or paragraph form. For application questions, connect the concept to daily life, such as wires, utensils, rusting, or salt formation.

This chapter is a bridge between theory and practical chemistry. It helps students understand why substances behave the way they do and why chemistry is useful in real life. A clear grasp of this unit also makes later chapters easier, especially carbon compounds, acids and bases, and chemical reactions.

Conclusion

Metals and non-metals is a foundational chapter in Class 10 Science because it explains the basic behaviour of two major groups of elements. It shows how metals and non-metals differ in their physical and chemical properties, how they form ions and ionic compounds, how the reactivity series works, and why corrosion and alloys are important in everyday life. The chapter also introduces the idea that chemical behaviour is linked to atomic structure and electron transfer.

This unit is valuable not just for examinations, but for understanding the materials and reactions that shape the world around us. Once students learn this chapter properly, they gain a stronger base for future chemistry topics and a better understanding of how science explains common objects, processes, and industrial applications. It is a chapter where observation, reasoning, and practical use all come together.