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 → Periodic table ↓


Introduction to the Periodic Table


The periodic table is one of the most important tools in the field of chemistry. It organizes all the known chemical elements in a systematic way. This table helps chemists understand the relationships between elements and predict the properties of elements that have not yet been discovered. In this lesson, we will explore the basics of the periodic table and how it can be used.

What is the Periodic Table?

The periodic table is a chart that displays all the known chemical elements. Each element has a unique symbol, usually derived from its English or Latin name, and is arranged by its atomic number, which is the number of protons in an atom's nucleus. The periodic table is divided into rows called periods and columns called groups.

History of the Periodic Table

The concept of grouping elements dates back to the 19th century. Russian chemist Dmitry Mendeleev is often credited with creating the first periodic table in 1869. Mendeleev observed that when elements are arranged in order of increasing atomic mass, certain types of elements occur regularly. He left gaps for unknown elements, predicting their properties with remarkable accuracy. Later, Henry Moseley revised the table, arranging elements by atomic number rather than atomic mass, creating the modern periodic table we use today.

Structure of the Periodic Table

The periodic table is structured in horizontal rows and vertical columns. Understanding this structure will help us use the table effectively.

Period

Periods are horizontal rows in the periodic table and are numbered from 1 to 7. Each period indicates the number of electron shells in an atom. For example, elements in the first period have electrons in one shell, while elements in the second period have electrons in two shells.

H He

For example, hydrogen (H) and helium (He) are in the first period and have one electron shell. This is clearly shown in the diagram above.

Group

Groups are the vertical columns of the periodic table and there are a total of 18 groups. Elements in the same group share similar chemical properties because they have the same number of electrons in their outermost shell, also called valence electrons.

Took No K RB C

For example, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs) all belong to group 1, also known as the alkali metals. As shown in the figure above, these elements have similar chemical properties and react vigorously with water.

Types of Elements in the Periodic Table

Elements in the periodic table can be classified into metals, nonmetals, and metalloids based on their properties.

Metals

Most of the elements in the periodic table are metals. They are found on the left side and in the middle of the table. Metals are typically shiny, malleable, ductile, and good conductors of electricity and heat. Examples of metals include iron (Fe), copper (Cu), and gold (Au).

Nonmetals

Nonmetals are found in the upper right portion of the periodic table. They are generally not shiny, not malleable, not ductile, and are poor conductors of electricity and heat. Examples of nonmetals include oxygen (O), carbon (C), and sulfur (S).

Metalloids

Metalloids have properties that are intermediate between metals and nonmetals. They are found along the zig-zag line separating metals and nonmetals on the periodic table. Examples of metalloids include silicon (Si) and arsenic (As).

Important Groups in the Periodic Table

Some groups in the periodic table have special names that reflect their unique properties. Let's take a look at some of them:

Alkali Metals (Group 1)

The alkali metals are highly reactive, especially with water, and are always found in nature as compounds rather than as free elements. These include lithium (Li), sodium (Na), and potassium (K).

Alkaline Earth Metals (Group 2)

The alkaline earth metals are less reactive than the alkali metals, but still form ions easily. These include beryllium (Be), magnesium (Mg), and calcium (Ca).

Halogens (Group 17)

Halogens are very reactive nonmetals and are often found in nature as salts. These include fluorine (F), chlorine (Cl), and iodine (I).

Noble gases (group 18)

The noble gases are inert and do not easily form compounds because they have a full valence electron shell. These include helium (He), neon (Ne), and argon (Ar).

Periodic Law

According to the periodic law, the properties of elements are periodic functions of their atomic numbers. This means that when elements are arranged according to increasing atomic numbers, they show periodic repetition of similar properties.

Transition metal

Transition metals are found in groups 3 through 12. These are all metals and include elements such as iron (Fe), copper (Cu), and gold (Au). These elements are often characterized by multiple oxidation states and form colorful compounds.

Understanding Element Symbols

Each element in the periodic table is represented by a symbol, usually the first one or two letters of its name. For example, helium's symbol is He. This system of symbols allows chemists to quickly identify elements without using long names.

Using the Periodic Table

The periodic table is a valuable tool for predicting the properties and behavior of elements. By knowing where an element is located, you can determine many of its properties, such as whether it is a metal or a nonmetal, its reactivity, and atomic size. Here are examples of how to use the periodic table:

H He Li Be BCNOF Ne Na Mg Al Si PS Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

In the simplified table above, you can see that elements like hydrogen (H) and helium (He) are at the top, indicating that they are in the first period. In contrast, elements like potassium (K) and calcium (Ca) are in the fourth period, indicating that they have more electron shells.

Conclusion

The periodic table is much more than just a list of elements; it is a powerful tool that reveals the relationships and properties of the elements. By exploring its structure, groups, and the information it provides, we gain insight into the fascinating world of chemistry. Understanding the periodic table helps us predict chemical reactions and understand the behavior of atoms, which is essential for anyone studying chemistry.


Grade 7 → 6.1


U
username
0%
completed in Grade 7

← Prev (6)
Periodic table
Next (6.2) →
Groups and periods

Comments 



Introduction to the Periodic Table

https://www.chemistryelite.com/g7/6.1?ceal=en