Grade 8
  1. Introduction to Chemistry  1.1. Nature and scope of chemistry  1.2. Importance of chemistry in daily life  1.3. Chemistry and its relation with other sciences  1.4. The role of chemistry in industry, medicine and the environment  1.5. Scientific investigation and experimental methods in chemistry
  2. Matter and its properties  2.1. Definition and classification of matter  2.2. Physical and chemical properties of matter  2.3. Law of conservation of matter  2.4. Extensive and Intensive Properties of Matter  2.5. Kinetic molecular theory of matter  2.6. States of matter: solids, liquids, gases, plasmas, and Bose-Einstein condensates  2.7. Changes in state and energy are involved  2.8. Diffusion and Brownian motion
  3. Elements, Compounds, and Mixtures  3.1. Definition and differences between elements, compounds, and mixtures  3.2. Atomic Structure and Atomic Number  3.3. Chemical symbols and formulas  3.4. Trends in the Periodic Table (Groups and Periods)  3.5. Classification of Elements: Metals, Nonmetals and Metalloids  3.6. Rare Earth Elements and Transition Metals  3.7. Types of mixtures: homogeneous and heterogeneous  3.8. Separation of Mixtures Using Physical and Chemical Methods
  4. Separation Techniques  4.1. Filtration, Sedimentation and Decantation  4.2. Evaporation and crystallization  4.3. Distillation and Fractional Distillation  4.4. Chromatography and its applications  4.5. Sublimation in the purification of compounds  4.6. The role of centrifugation in biochemical processes
  5. Atomic Structure  5.1. Dalton's atomic theory  5.2. Structure of the atom: protons, neutrons and electrons  5.3. Bohr's atomic model  5.4. Introduction to Quantum Mechanical Model  5.5. Electron Configuration and Energy Levels  5.6. Excitation and emission spectra  5.7. Isotopes and their applications
  6. Periodic Table and Chemical Trends  6.1. History and Development of the Periodic Table  6.2. Modern periodic law  6.3. Periodicity and trends in atomic and ionic sizes  6.4. Ionization Energy, Electron Affinity and Electronegativity  6.5. Introduction to Lanthanides and Actinides  6.6. Application of periodic trends in chemistry
  7. Chemical Bonding and Molecular Structure  7.1. Types of chemical bonds: ionic, covalent and metallic bonds  7.3. Polar and Nonpolar Molecules  7.4. Hydrogen bonding and its applications  7.5. Intermolecular forces: dipole-dipole, London dispersion force
  8. Chemical Reactions and Stoichiometry  8.1. Chemical Equations and Balance  8.2. Types of Chemical Reactions: Combination, Decomposition, Displacement and Redox  8.3. Introduction to stoichiometry and the mole concept  8.4. Limiting reactant in chemical equations  8.5. Reaction rate, catalyst, and factors affecting reaction rate
  9. Acids, Bases and Salts  9.1. Definition and Properties of Acids and Bases  9.2. Strong vs. Weak Acids and Bases  9.3. pH Scale and pH Calculation  9.4. Neutralization reactions  9.5. Buffer solutions and their importance  9.6. Applications of Acids, Bases and Salts in Daily Life
  10. Solutions and Solubility  10.1. Definition of Solution, Solute, and Solvent  10.2. Factors Affecting Solubility  10.3. Concentration units: molarity and molality  10.4. Saturated, unsaturated and supersaturated solutions  10.5. Concept of osmosis and reverse osmosis  10.6. Concentrative properties of solutions
  11. Gases and Gas Laws  11.1. Properties of gases  11.2. Introduction to Ideal and Real Gases  11.3. Boyle's Law, Charles' Law and Avogadro's Law  11.4. Ideal Gas Equation and Its Applications  11.5. Application of Gas Laws in Real Life
  12. Thermochemistry and energy transformation  12.1. Energy in Chemical Reactions  12.2. Exothermic vs. Endothermic Reactions  12.3. Heat and Enthalpy Changes  12.4. Calorimetry and heat transfer in reactions
  13. Metals and Nonmetals  13.1. Physical and Chemical Properties of Metals and Nonmetals  13.2. Reactivity Series of Metals  13.3. Corrosion and its prevention  13.4. Extraction of metals from ores  13.5. Uses of metals and non-metals in daily life
  14. Introduction to Organic Chemistry  14.1. Characteristics of carbon and organic compounds  14.2. Functional groups and their importance  14.3. Simple Hydrocarbons: Alkenes, Alkenes and Alkynes  14.4. Isomerism in organic compounds  14.5. Introduction to polymers and their uses
  15. Environmental Chemistry and Sustainability  15.1. Green Chemistry Principles  15.2. Effects of Chemical Pollution on Ecosystems  15.3. Acid rain and its effects  15.4. Ozone layer depletion and global warming  15.5. Waste Management and Recycling in Chemistry

Grade 8 ↓


Introduction to Chemistry


Chemistry is the scientific study of matter and the changes that occur in it. Matter is everything that has mass and occupies space. All around us, chemistry works in different ways, from the air we breathe to the food we eat. Basically, chemistry is about understanding what things are made of and how they interact with each other.

Let's start with the most basic: the atom. The atom is the smallest unit of matter that retains all of an element's chemical properties. Each element in the periodic table consists of one type of atom. For example, gold is made up of gold atoms, while oxygen is made up of oxygen atoms.

Understanding atoms

Atoms are made up of three smaller particles: protons, neutrons, and electrons. - Protons have a positive charge and are found in the nucleus at the center of the atom. - Neutrons have no charge and are also found in the nucleus. - Electrons are negatively charged and orbit around the nucleus in often complex paths.

Simple model of an atom showing a nucleus with protons and neutrons and orbiting electrons.

The number of protons in the nucleus of an atom tells us the atomic number of that element. For example, hydrogen has 1 proton, so its atomic number is 1. If you add a neutron to an atom, you create an isotope of that element. An isotope is an atom that has the same number of protons but a different number of neutrons.

Molecules and compounds

Atoms can combine to form molecules. A molecule is a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can participate in a chemical reaction. For example, water is a molecule composed of 2 hydrogen atoms and 1 oxygen atom. The chemical formula of water is written as:

H 2 O

When two or more different types of atoms are joined together, the substance is called a compound. Table salt is an example of a compound made up of sodium (Na) and chlorine (Cl), which chemically combine to form sodium chloride, which has the chemical formula:

NaCl
No Chlorine

Chemical reactions

Chemical reactions occur when substances combine in new ways to form new substances with different properties. A simple example of a chemical reaction is hydrogen and oxygen combining to form water:

2H 2 + O 2 → 2H 2 O

In a chemical reaction, the substances that start the reaction are called reactants, and the substances that are formed are called products. Reactions involve the making and breaking of chemical bonds. The arrow in a chemical equation shows the direction of the reaction.

States of matter

Matter can exist in different states. The three primary states of matter are solid, liquid, and gas:

  • Solids: They have definite shape and volume. The particles in a solid are very closely packed together and vibrate in place.
  • Liquids: have a fixed volume but take the shape of their container. The particles in a liquid are still close together but can move past one another.
  • Gases: They have no definite shape or volume. The particles are far apart and move around freely.

A common example to understand these states is water. Water in its solid form is ice. In its liquid form, it is what we drink as water. In its gas form, it becomes water vapor or steam.

Solid Liquid Gas

Periodic table

The periodic table is a chart that arranges all known elements according to increasing atomic number and groups them based on similar chemical properties. Elements in the same column, called groups, share similar properties. For example, in group 1, all elements are metals that react with water.

The groups are numbered from 1 to 18. The rows in the periodic table are called periods and these are numbered from period 1 to 7. Along with classifying elements as metals, nonmetals, or metalloids, the periodic table helps us predict the chemical reactions and properties of the elements.

H He Took Happen

Acids and bases

Chemistry also includes the study of acids and bases, which are special types of chemical compounds. Acids are substances that release hydrogen ions (H+) when dissolved in water. Common examples include vinegar and lemon juice. Bases release hydroxide ions (OH–) and include substances such as soap and baking soda.

HCl → H+ + Cl-

When acids and bases are mixed, they neutralize each other, forming water and salt:

HCl + NaOH → NaCl + H2O

Conclusion

Chemistry is a fascinating and essential science that helps us understand the world around us. From the structure of atoms to complex chemical reactions, everything in chemistry follows patterns and rules, making it possible for scientists to predict how substances will behave and interact.

With a strong foundation based on knowledge of atoms, molecules, reactions, and the periodic table, students can learn more about the wonders of chemistry and its impact on daily life and technology. This introduction serves as a stepping stone into the vast and exciting field of chemistry.


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Introduction to Chemistry

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