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 → Matter and its properties ↓


Definition of Matter


Matter is a fundamental concept in chemistry and physics that refers to anything that occupies space and has mass. This definition may seem simple, but it opens up a world of understanding about the universe and our surroundings. Everything we see and what we don’t see is matter. From a grain of sand to the vast oceans, clouds in the sky to complex living organisms, they are all made up of matter. Let’s take a deeper look at matter, its properties and its importance.

Understanding matter: the building blocks of everything

To understand matter, imagine building a house out of blocks. Each block represents a tiny unit of matter. Together, these blocks can form different shapes and structures. Likewise, matter is made up of very small particles called atoms. These atoms can combine to form molecules, which are essentially the blocks that make up everything in our universe.

Atoms and molecules: the invisible foundations

An atom is the smallest unit of an element that retains its chemical properties. Atoms are the building blocks of elements such as hydrogen, oxygen and carbon. When atoms join together, they form molecules. For example, two hydrogen atoms and one oxygen atom form a molecule of water, which is represented by the chemical formula H 2 O

A molecule is simply a group of two or more atoms bonded together. For example, carbon dioxide is a molecule consisting of one carbon atom and two oxygen atoms. Its chemical formula is CO 2.

// Chemical example:
H 2 O --> water molecule
CO 2 --> Carbon dioxide molecule

States of matter

Matter usually exists in three different states: solid, liquid, and gas. Each state has its own distinct characteristics based on how the atoms and molecules are arranged and move.

Solid state

Atoms and molecules in solids are tightly packed together in a certain structure. This close arrangement gives solids a definite shape and volume. For example, a piece of wood maintains its shape even if you move it from one place to another.

In the illustration above, consider each rectangle as an atom of a solid material that is closely connected to each other.

Fluid state

Liquids have a fixed volume but take the shape of their container. This is because the atoms or molecules in a liquid are not as tightly packed as those in solids. They have some freedom to move around, which allows liquids to flow and take the shape of their container. Water is a great example of a liquid

In this diagram, notice how the shapes (representing molecules) are close together but not in fixed positions, allowing for fluid movement.

Gas state

In the gaseous state, atoms and molecules move around freely and expand to fill the container they are in. Gases have neither a definite shape nor a definite volume. Air is a mixture of gases such as oxygen and nitrogen.

This diagram shows the dispersed arrangement of gas molecules that float freely.

Physical and chemical properties of matter

To understand matter better, it is important to know about its properties. These properties help us identify and classify different substances based on their characteristics.

Physical properties

Physical properties are characteristics that can be seen or measured without changing the chemical identity of the substance. These include:

  • Colour: Visual appearance in relation to shade.
  • Density: The mass of a substance per unit volume.
  • Melting point: The temperature at which a solid changes into a liquid.
  • Boiling point: The temperature at which a liquid changes into a gas.

Chemical properties

Chemical properties describe how a substance combines with other substances to form new substances. These include:

  • Reactivity: How a substance reacts to other chemicals.
  • Flammability: How easily a substance can ignite.
  • pH level: A measure of acidity or alkalinity.

The importance of understanding the topic

Understanding matter is very important because it is the basis for many scientific studies and practical applications. Here are some reasons why it is important to understand matter:

  • Development of new materials: Knowledge of the properties of materials helps scientists create new materials for various uses, such as stronger metals, lighter-weight compounds, and advanced ceramics.
  • Environmental understanding: Knowing how different substances interact is important for understanding and solving environmental issues such as pollution and resource depletion.
  • Medical advances: Many medical advances depend on an understanding of biochemistry, which is the study of chemical processes within living organisms.

As you can see, matter and its properties are the cornerstone of the natural world. It plays a vital role not only in science but also in our everyday lives. By understanding what matter is and how it behaves, we gain insight into the universe and the means to innovate and solve problems in various fields.


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Definition of Matter

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