Introduction of Elements, Compounds, and Mixtures

All the matter in our knowledge can be broken down into pure substances and mixtures. Pure substances can be further broken down into elements and compounds. Elements and compounds have a constant chemical composition, and thus they have uniform chemical properties.

Pure water extracted from a plant and obtained by purifying tap water will be made up of a combination of hydrogen and oxygen that is constant irrespective of the source. But mixtures are not so. They are substances formed by physically mixing other substances. The components of a mixture do not form chemical bonds like they do in a compound. It is essential to introduce elements, compounds, and mixtures since these form the basis of studying matter and its properties.

Elements

In chemistry, an element is a pure substance made up of only one type of atom. All the atoms of an element will have the same number of protons in their nucleus. This number of protons represents the atomic number of the element. Elements are placed in the periodic table according to their atomic number.

Elements can be categorised into metals, non-metal, and metalloids in the periodic table.

• Metals: Metallic elements are usually found on the left side of the periodic table. These elements share some characteristics such as:

1. Can act as conductors of electricity.

2. They are typically ductile or can be drawn into wires.

3. Are malleable or can be beaten into sheets.

4. Have a shiny surface.

5. They can sometimes be magnetic.

6. They are usually electropositive.

7. Some examples of metals are Iron (Fe), aluminium (Al), copper (Cu), mercury (Hg), and lead (Pb).

• Non-metals: These elements are placed on the right side of the periodic table. They share specific properties that are used to categorise them as non-metal. These are as follows:

1. They do not have a shiny appearance.

2. Usually they do not conduct electricity.

3. Are not malleable.

4. Are not ductile.

5. They are generally electronegative.

6. Non-metals are not magnetic.

7. Some examples of non-metals are Fluorine (F), Chlorine (Cl), Iodine (I), etc.

• Metalloids: These are elements that have properties that are a mixture of both metals and non-metals. There is no universally recognised definition of metalloids. Even so, the most agreed upon metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium.

Compounds

A chemical compound results from two or more elements combining through a chemical process. When elements combine through chemical processes, bonds are formed between their atoms by a sharing or transference of electrons. This process is known as chemical bonding. Most elements on earth combine to form compounds. These compounds play an essential part in the life of our planet since it is through a combination of elements and compounds that the building blocks of all organic matter are formed. These are important because they also form salts necessary for the survival of organisms.

Chemical compounds are made up of atoms that combine in a fixed ratio, and the molecules thus formed occupy a defined space. These atoms are held together by chemical bonds based on which compounds can be classified as:

• Molecular compounds that have covalent bonds.

• Salts that have ionic bonding

• Intermetallic compounds that have metallic bonding.

• Complexes that have coordinate covalent bonds.

Mixtures

When two or more substances are mixed but are combined by a chemical process, the result is a mixture. This means that the components retain their natural and chemical properties. In compounds, the electrons realign to form a substance with its properties, often different from the parent components. Alloys, suspensions, colloids, and solutions are types of mixtures.

Mixtures can be categorised into the following:

• Heterogeneous mixtures: When the substances combined in the mixture can be easily seen and separated, the mixture is heterogeneous. Examples include conglomerate rock, sand and iron filing powder, sand and water, a salad, etc.

• Homogenous mixture: In these mixtures, the components cannot be distinguished and require special procedures to separate them. Examples include mayonnaise, air, saline solution, most alloys, etc.  

This was an introduction of elements, compounds, and mixtures. As the syllabus progresses, the concepts learnt in this introduction will be helpful in understanding more advanced concepts.

Conclusion

Chemistry is the study of how matter behaves and the factors that influence this behaviour. An introduction of elements, compounds, and mixtures is crucial because it is a part of chemistry fundamentals. Understanding the concepts that form the classification of matter makes it easier to progress to more complex concepts of the subject. These complex concepts are often rooted in more straightforward but fundamental ideas.