Grade 7
  1. Introduction to Chemistry  1.1. What is Chemistry?  1.2. Importance of chemistry in daily life  1.3. Branches of chemistry  1.4. Scientific Method in Chemistry  1.5. Laboratory Safety Rules and Precautions  1.6. Common Laboratory Equipment and Their Uses  1.7. Units of measurement in chemistry
  2. Matter and its properties  2.1. Definition of Matter  2.2. Classification of matter  2.3. Properties of matter  2.3.1. Physical properties  2.3.2. Chemical properties  2.4. States of matter  2.4.1. Solid state  2.4.2. Fluid state  2.4.3. Gaseous state  2.4.4. Plasma and Bose–Einstein condensates  2.5. Changes in the states of matter  2.5.1. Melting and freezing  2.5.2. Evaporation and Condensation  2.5.3. Sublimation and deposition  2.6. Density and its applications  2.7. Diffusion and its importance
  3. Elements, Compounds, and Mixtures  3.1. Definition of the element  3.2. Classification of elements  3.3. Metals, Nonmetals and Metalloids  3.4. Noble gases and their properties  3.5. Introduction to the Periodic Table  3.6. Definition of Compound  3.7. Properties of Compounds  3.8. Introduction to Chemical Formulas  3.9. Definition of Mixture  3.10. Types of mixtures  3.10.1. Homogeneous mixture  3.10.2. Heterogeneous mixtures  3.11. Difference Between Compounds and Mixtures  3.12. Solutions, Colloids and Suspensions
  4. Separation of mixtures  4.1. Need for separation of mixtures  4.2. Separation methods  4.2.1. Filtration  4.2.2. Sedimentation and decantation  4.2.3. Evaporation  4.2.4. Crystallization  4.2.5. Distillation  4.2.6. Chromatography  4.2.7. Magnetic Separation  4.2.8. Centrifugation
  5. Atomic Structure  5.1. Introduction to Atoms  5.2. Structure of the atom  5.2.1. Nucleus and electron cloud  5.3. Subatomic particles  5.3.1. Proton  5.3.2. Neutron  5.3.3. Electrons  5.4. Atomic number and mass number  5.5. Isotopes and their uses  5.6. Ions and ion formation
  6. Periodic table  6.1. Introduction to the Periodic Table  6.2. Groups and periods  6.3. Trends in the Periodic Table  6.3.1. Atomic Size  6.3.2. Metallic and non-metallic character  6.3.3. Electronegativity  6.3.4. Reactivity of the elements  6.4. Alkali metals and their properties
  7. Chemical bond  7.1. Why do atoms form bonds?  7.2. Types of chemical bonds  7.2.1. Ionic bond  7.2.2. Covalent bond  7.2.3. Metal Bond  7.3. Properties of Ionic and Covalent Compounds  7.4. Intermolecular forces
  8. Chemical reactions  8.1. Introduction to Chemical Reactions  8.2. Signs of a chemical reaction  8.3. Types of Chemical Reactions  8.3.1. Combination Reactions  8.3.2. Decomposition reactions  8.3.3. Displacement reactions  8.3.4. Double displacement reactions  8.3.5. Combustion reactions  8.4. Law of conservation of mass  8.5. Balancing simple chemical equations
  9. Acids, Bases and Salts  9.1. Definition of Acid and Base  9.2. Properties of Acids  9.3. Properties of bases  9.4. pH Scale and Indicators  9.5. Neutralization reactions  9.6. Common Acids and Bases in Everyday Life  9.7. Preparation and use of salts  9.8. Strong and weak acids and bases
  10. Solutions and Solubility  10.1. Definition of Solution  10.2. Components of the solution  10.2.1. Solvent  10.2.2. solute  10.3. Factors Affecting Solubility  10.4. Concentration of solutions  10.5. Saturated and unsaturated solutions  10.6. Colloids and suspensions  10.7. Solubility curve and its interpretation
  11. Air and atmosphere  11.1. Composition of air  11.2. Properties of gases in the air  11.3. Importance of Oxygen and Carbon Dioxide  11.4. Air pollution and its effects  11.5. Greenhouse effect and global warming  11.6. Ways to reduce air pollution  11.7. Ozone layer and its importance
  12. Water and its importance  12.1. Properties of Water  12.2. Water as the universal solvent  12.3. Importance of water for life  12.4. Water pollution and its effects  12.5. Water Purification  12.5.1. Filtration  12.5.2. boil  12.5.3. Chlorination in water purification  12.5.4. reverse osmosis  12.6. Hard and soft water  12.7. Water cycle and its importance
  13. Fuel and energy  13.1. Types of fuel  13.1.1. Fossil fuels  13.1.2. Renewable energy sources  13.2. Combustion and energy release  13.3. Global warming and its effects  13.4. Alternative sources of energy  13.5. Ways to conserve energy
  14. Metals and Nonmetals  14.1. Physical and chemical properties of metals  14.2. Physical and Chemical Properties of Non-Metals  14.3. Difference Between Metals and Nonmetals  14.4. Uses of metals and nonmetals  14.5. Corrosion of metals and its prevention  14.6. Alloys and their importance
  15. Plastics and polymers  15.1. Natural and synthetic polymers  15.2. Properties of plastics  15.3. Biodegradable and Non-Biodegradable Plastics  15.4. Environmental impact of plastic  15.5. Recycling and waste management in plastics and polymers  15.6. Daily Uses of Polymers
  16. Introduction to Organic Chemistry  16.1. Basic definitions of organic chemistry  16.2. Carbon Compounds in Daily Life  16.3. Hydrocarbons  16.4. Simple functional groups (alcohols and carboxylic acids)  16.5. Importance of organic compounds in industry

Grade 7 → Metals and Nonmetals ↓


Physical and chemical properties of metals


Metals are a large group of elements that are generally characterized by their lustrous appearance, good conductivity of heat and electricity, malleability, ductility, and tendency to lose electrons in chemical reactions to form positive ions. This lesson will explore the physical and chemical properties of metals in detail.

Physical properties of metals

Physical properties of metals are those characteristics that can be observed without changing the identity of the substance. Some of the main physical properties of metals are as follows:

1. Shiny

When metals are polished, they appear shiny, which is called metallic lustre. This happens because metals can reflect light effectively.

Metal

2. Flexibility

Malleability is the ability of metals to be hammered into thin sheets. For example, gold is highly malleable and can be hammered into sheets as thin as leaves.

Gold Sheet

3. Flexibility

Metals can be drawn into thin wires. For example, copper wires are widely used in electrical wiring.

Copper Wire

4. Good conductors of heat and electricity

Metals are excellent conductors of heat and electricity. This is because metals have free electrons that can move easily through the structure. Silver and copper are the best conductors.

5. High density

Most metals have a high density. This means that they are heavy for their size. For example, lead is dense and feels heavy.

6. High melting and boiling point

Metals generally have high melting and boiling points, which means they require a lot of heat to change state. The melting point of iron is 1538°C (Iron: 1538°C).

7. Madhur

When metal is struck, a ringing sound is produced. This quality is called sonority. Because of this quality, bells are often made from metals like bronze.

Chemical properties of metals

The chemical properties of metals describe their behavior when they undergo chemical changes.

1. Reaction with oxygen

Metals react with oxygen to form metal oxides. For example:

4Na + O2 → 2Na2O (Sodium oxide) 2Mg + O2 → 2MgO (Magnesium oxide)

Most metal oxides are alkaline in nature and form alkali when dissolved in water.

2. Reaction with water

Metals can react with water to produce metal hydroxide and hydrogen gas, although not all metals react in the same way.

2Na + 2H2O → 2NaOH + H2 ↑ (Sodium hydroxide)

Some metals like gold and platinum do not react with water.

3. Reaction with acids

Metals react with acids to form salts and hydrogen gas.

Zn + 2HCl → ZnCl2 + H2 ↑ (Zinc chloride)

This reaction is often used in the laboratory to prepare hydrogen gas.

4. Reaction with bases

Some metals react with strong bases such as sodium hydroxide to form complex salts.

2Al + 2NaOH + 6H2O → 2NaAl(OH)4 + 3H2 ↑ (Sodium aluminate)

5. Displacement reactions

In these reactions, more reactive metals displace less reactive metals from their compounds.

CuSO4 + Zn → ZnSO4 + Cu (Copper sulphate and zinc reaction)

Summary

In short, metals are characterized by their ability to conduct heat and electricity, their lustrous appearance, malleability, ductility, and their high density and melting point. Chemically, they readily participate in reactions, often form oxides, react with water and acids, and participate in displacement reactions. Understanding these properties helps us use metals effectively in various industries and applications.


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Physical and chemical properties of metals

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