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 Non-Metals


Introduction

In the world of chemistry, elements are broadly classified into metals and nonmetals. This division is based on their physical and chemical properties. Nonmetals, as the name suggests, are elements that do not exhibit the typical properties of metals. They have unique characteristics that set them apart, and they play diverse roles in various chemical reactions and processes. In this lesson, we will explore the physical and chemical properties of nonmetals, their differences from metals, and their applications.

Physical properties of nonmetals

Nonmetals exhibit a wide variety of physical properties. Unlike metals, nonmetals can be gases, liquids, or solids at room temperature. Let's take a closer look at some of these properties.

State and appearance

Nonmetals can appear in different states of matter:

  • Gases: Many nonmetals, such as O 2 (oxygen) and N 2 (nitrogen), are gases under standard conditions.
  • Solid: Nonmetals like carbon, sulfur and phosphorus are solids at room temperature.
  • Liquid: Bromine is a nonmetal that exists in liquid form at room temperature.

Color and texture

Non-metals have different colors and textures. For example, sulfur is yellow and brittle, while iodine is dark brown or purple and looks like crystals.

Brittleness

Nonmetals are generally brittle in the solid state. They break or shatter easily when force is applied. This is in contrast to metals, which are malleable.

Sulphur

Chemical properties of nonmetals

Nonmetals are known for their unique chemical properties, which are quite different from those of metals. These properties make nonmetals essential for various chemical reactions and compounds.

High electronegativities

Nonmetals have high electronegativities, which means they attract electrons toward themselves during chemical reactions. This is why nonmetals often form covalent bonds, sharing electrons with other atoms.

Acidic oxides

When nonmetals react with oxygen, they form oxides that are usually acidic. For example:

SO 2 + H 2 O → H 2 SO 3 (sulfurous acid)

In this reaction, sulfur dioxide reacts with water to form sulfurous acid.

Oxygen

Poor conductor of electricity

Nonmetals are generally poor conductors of electricity. This property is particularly evident in solid nonmetals, which do not have freely moving charges to carry electric current.

Jet

Nonmetals can be highly reactive, especially with metals. For example, chlorine reacts vigorously with sodium to form sodium chloride (table salt):

2Na + Cl 2 → 2NaCl

Common nonmetals and their uses

Given below are some common nonmetals and their applications in daily life and industry.

Carbon

Carbon is a very versatile nonmetal, existing as diamond, graphite, and fullerenes. It is used in:

  • Diamonds: Jewellery and cutting tools.
  • Graphite: In pencils and as a lubricant.
  • Carbon compounds: Organic Chemistry and Fuels.
Lead

Oxygen

Oxygen supports life and is important in respiration. It is also used to aid combustion in welding and industrial processes.

Nitrogen

Nitrogen accounts for about 78% of the Earth's atmosphere. It is used in fertilizers, explosives, and as a refrigerant.

Conclusion

Nonmetals are essential elements with diverse properties and applications. Their ability to form a wide range of compounds important to life and industry highlights their importance. From supporting life through oxygen to forming the backbone of organic chemistry with carbon, nonmetals play a vital role in our daily lives and the world around us.


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Physical and chemical properties of metals
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