Grade 9
  1. Matter and its nature  1.1. Introduction to matter  1.2. Physical and chemical properties of matter  1.3. States of matter  1.3.1. Solid state  1.3.2. Fluid state  1.3.3. Gaseous state  1.3.4. Plasma and Bose–Einstein condensate  1.4. Changes in the states of matter  1.4.1. Melting and freezing  1.4.2. Evaporation and Condensation  1.4.3. Sublimation and deposition  1.5. Classification of matter  1.6. Elements, Compounds, and Mixtures  1.7. Pure substances and impurities  1.8. Separation Techniques  1.8.1. Filtration  1.8.2. Distillation  1.8.3. Crystallization  1.8.4. Chromatography  1.8.5. Centrifugation  1.8.6. Sublimation  1.8.7. Decantation and sedimentation
  2. Atomic Structure  2.1. Discovery of atoms  2.2. Dalton's atomic theory  2.3. Structure of the atom  2.4. Subatomic particles  2.5. Atomic number and mass number  2.6. Isotopes and Isobars  2.7. Electronic configuration  2.8. Bohr's atomic model  2.9. Modern Atomic Model (Quantum Mechanical Model - Introduction)  2.10. Valency and chemical bonding
  3. C hemical reactions and equations  3.1. Introduction to Chemical Reactions  3.2. Chemical Equation Formulation  3.3. Balancing Chemical Equations  3.4. Types of Chemical Reactions  3.4.1. Combination Reactions  3.4.2. Decomposition reactions  3.4.3. Displacement reactions  3.4.4. Double displacement reactions  3.4.5. Redox reactions  3.4.6. Endothermic and Exothermic Reactions  3.5. Effects of chemical reactions  3.6. Energy Changes in Chemical Reactions  3.7. Catalysts and their role in reactions
  4. Periodic table and periodicity  4.1. History of Periodic Classification  4.2. Mendeleev's periodic table  4.3. Modern Periodic Table  4.4. Periods and groups in the periodic table and periodicity  4.5. Trends in the Periodic Table  4.5.1. Atomic size  4.5.2. Ionization Energy  4.5.3. Electron affinity  4.5.4. Electronegativity  4.5.5. Metallic and Non-Metallic Properties  4.6. Noble gases and their properties
  5. Chemical bond  5.1. Introduction to Chemical Bonding  5.2. Types of chemical bonds  5.2.1. Ionic bond  5.2.2. Covalent bond  5.2.3. Metallic bond  5.2.4. Hydrogen bonding  5.2.5. Van der Waals force  5.3. Properties of Ionic and Covalent Compounds  5.4. Molecular Structure and Geometry (VSEPR Theory - Basics)
  6. Acids, Bases and Salts  6.1. Introduction to Acids and Bases  6.2. Properties of Acids  6.3. Properties of bases  6.4. pH scale and its importance  6.5. Indicators and their uses  6.6. Neutralization reactions  6.7. Strength of Acids and Bases (Strong vs. Weak)  6.8. Preparation of salts  6.9. Uses of acids, bases and salts in daily life
  7. Metals and Nonmetals  7.1. Physical Properties of Metals  7.2. Physical Properties of Nonmetals  7.3. Chemical properties of metals  7.4. Chemical Properties of Nonmetals  7.5. Reactivity Series of Metals  7.6. Extraction of metals  7.7. Corrosion and its prevention  7.8. uses of metals and nonmetals
  8. Carbon and its compounds  8.1. Introduction to Carbon  8.2. Allotropes of carbon (diamond, graphite, fullerene)  8.3. Hydrocarbons  8.3.1. Hydrocarbons  8.3.2. Alkene  8.3.3. Alkynes  8.4. Functional groups in organic chemistry  8.5. Isomerism in organic compounds  8.6. Alcohols and Carboxylic Acids  8.7. Soaps and detergents  8.8. Polymers (Introduction to Natural and Synthetic Polymers)
  9. Solutions and Mixtures  9.1. Types of mixtures  9.2. Homogeneous and Heterogeneous Mixtures  9.3. Concentration of solutions  9.4. Solubility and factors affecting solubility  9.5. Suspensions and Colloids  9.6. Saturated, unsaturated and supersaturated solutions
  10. Air and atmosphere  10.1. Composition of air  10.2. Role of gases in the atmosphere  10.4. Acid rain and its effects  10.5. Greenhouse effect and global warming  10.6. Ozone layer and its depletion  10.7. Air pollution control measures
  11. Water and its importance  11.1. Composition and properties of water  11.2. Hardness of water (temporary and permanent hardness)  11.3. Causes of water pollution  11.4. Effects of Water Pollution  11.5. Water purification methods (filtration, boiling, chlorination)
  12. Industrial Chemistry  12.1. Introduction to Industrial Chemistry  12.2. Important industrial chemicals (sulfuric acid, ammonia, sodium hydroxide)  12.3. Chemical processes in industry  12.4. Uses of Industrial Chemistry in Daily Life  12.5. Environmental impact of industrial chemical processes

Grade 9 → Chemical bond ↓


Types of chemical bonds


The chemical bond is a fundamental concept in chemistry that describes how atoms come together to form molecules. Atoms bond together in various ways to form stable structures. These bonds involve interactions between electrons, which are negatively charged particles that surround the atom's nucleus. Understanding the types of chemical bonds is important for understanding how different substances form and how they interact with each other. In this comprehensive guide, we'll explore the main types of chemical bonds: ionic bonds, covalent bonds, and metallic bonds. We'll take a deep look at their characteristics, the way they form, and how they affect the properties of compounds.

Ionic bond

Ionic bonds form when one atom donates one or more electrons to another atom, forming ions. This usually occurs between metals and nonmetals. The metal atom loses electrons and becomes a positively charged ion, while the nonmetal atom gains electrons and becomes a negatively charged ion. Ionic bonds form as a result of the attraction between oppositely charged ions.

An example of an ionic compound is sodium chloride (NaCl), commonly known as table salt. In this compound, a sodium atom (Na) donates one electron to a chlorine atom (Cl), resulting in a sodium ion (Na+) and a chloride ion (Cl-). The attraction between these ions forms an ionic bond.

No Chlorine

Ionic compounds generally have high melting and boiling points because of the strong attraction between the ions. They also tend to conduct electricity when dissolved in water and melted, because the ions are able to move around freely and carry a charge.

Covalent bonds

Covalent bonds are formed when two atoms share one or more electron pairs. This bond type typically occurs between non-metal atoms. Unlike ionic bonding, where electrons are transferred, covalent bonding involves sharing electrons to achieve a stable electron configuration.

Water (H2O) is an example of a covalent compound. In water, each hydrogen atom shares one electron with an oxygen atom, resulting in two covalent bonds. Oxygen shares its electrons with hydrogen atoms to complete its outer shell.

Hey H H

Covalent bonds can be single, double, or triple, depending on the number of shared electron pairs. For example, a single covalent bond involves one pair of shared electrons, as in hydrogen gas (H2). A double bond, found in oxygen gas (O2), involves two pairs of shared electrons. Nitrogen gas (N2) has a triple bond, with three pairs of electrons shared.

The physical properties of covalent compounds vary widely. Some, such as carbon dioxide (CO2), are gases at room temperature, while others, such as diamond, are solids. Covalent compounds generally have lower melting and boiling points than ionic compounds and do not conduct electricity in their solid or dissolved states.

Metal bonding

Metallic bonds are formed between metal atoms. In this type of bond, electrons are not shared or transferred between individual atoms, but rather they move freely throughout the structure, forming a "sea of electrons." This creates a strong attraction between the positively charged metal ions and the delocalized electrons.

This type of bond is responsible for the unique properties of metals: malleability, ductility, electrical conductivity, and luster. Metals such as copper (Cu), iron (Fe), and aluminum (Al) exhibit these characteristics because of metallic bonds within their structure.

Sea of Electrons

Metallic bonds are characterized by their strength and the mobility of electrons, which allows them to conduct electricity and heat efficiently. This is why metals are often used in electrical wiring and cookware.

Comparison and examples

In short, the type of chemical bond significantly affects the properties of a substance. Let's take a look at some of the main differences between types of bonds:

  • Ionic bond: involves transfer of electrons, resulting in high melting and boiling points, conduction of electricity in solution, and often formation of crystalline solids.
  • Covalent bonds: involve sharing of electrons, can form gases, liquids, or solids, generally have lower melting and boiling points than ionic compounds, and do not conduct electricity.
  • Metallic bond: It consists of a set of electrons which is responsible for metallic properties like conductivity, malleability, and lustre.

Here are additional examples of compounds and the types of bonds they contain:

  • Magnesium oxide (MgO): An ionic compound formed between magnesium (Mg) and oxygen (O). Magnesium donates two electrons to the oxygen, resulting in a strong ionic bond.
  • Carbon dioxide (CO2): A covalent compound containing two double bonds between carbon (C) and oxygen (O).
  • Iron (Fe): A metallic element in which atoms are bound to each other by metallic bonds, allowing iron to be cast and to conduct electricity.

Understanding these bonds is important in chemistry as it helps predict the properties of compounds, their reactions, and their use in everyday life. Each type of bond offers different advantages that are used in many applications in various fields such as medicine, engineering, and technology.

Visualization of chemical bonds

Let's look further with some visuals to help us understand the concept of chemical bonding. Consider a simple model of bonding to visualize the interactions between electrons and atoms.

Ionic bonding view

Na+ Cl-

In the ionic bonding view, the complete transfer of one electron from sodium (Na) to chlorine (Cl) can be seen, resulting in the formation of ions and consequently an ionic compound.

Covalent bond view

Hey H H

In the covalent bond view, note the shared electron pairs between the oxygen and hydrogen atoms. This sharing results in the stable formation of a water molecule.

Metal bondage scene

Sea of Electrons

The metallic bond view shows delocalized electrons, often referred to as a "sea of electrons", which move freely around in the solid, giving metals their distinctive properties.

In conclusion, chemical bonding is a fascinating area of chemistry that explains how elements interact and form the substances we see around us. The types of chemical bonds – ionic, covalent, and metallic – determine the physical and chemical properties of compounds, creating a diverse and versatile range of materials used in various aspects of everyday life.

Understanding the different types of chemical bonds provides a foundation for learning more advanced topics in chemistry and exploring how these principles are applied in science and industry.


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Types of chemical bonds

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