The 20 Best Chemistry Terms Students Need to Know

The basis of learning chemistry is understanding essential terms. If you are studying to pass IGCSE, A-levels, WAEC, or KCSE, or you want to revise your basic knowledge of science, the simplest definitions are the key to your success. This post will examine 20 fundamental chemistry terms and their definitions, presented in an easy-to-understand and accessible format for students.

Atom

 It is the smallest unit of an element that maintains the chemical characteristics of the component. It has neutrons, protons, and electrons.

Element 

An element is a pure substance consisting of a single type of atom. Examples are Hydrogen (H), oxygen (O), and gold (Au).

Molecule

A molecule is a group of two or more atoms that are joined together. Molecules may either be elements (for instance, O2) or compounds (for example, H2O).

Compound 

A compound is a chemical combination of two or more elements in definite proportions. Therefore, to illustrate, water (H2O) is a compound consisting of hydrogen and oxygen.

Mixture 

A mixture is a physical mixture of two or more substances in which the individual properties are retained. Physical means, such as filtration or distillation, may be used to separate mixtures.

Chemical Reaction 

A chemical reaction is a process in which substances (reactants) are transformed into new substances (products). Indications include a change in color, a change in temperature, the production of gas, or the formation of a precipitate.

Acid

 An acid is a substance that liberates hydrogen ions (H+) in solution. A pH of less than 7 indicates the presence of acids. Some of the acids include hydrochloric acid (HCl) and sulfuric acid (H2SO4).

Base 

A base is a substance that liberates hydroxide ions (OH-) in solution. Bases are pH levels that are more than 7. Some of the bases encompass sodium hydroxide (NaOH) and ammonia (NH3).

pH

A pH scale is used to measure the acidity or basicity of a solution. It ranges from 0 (very acidic) to 14 (very basic), with a neutral value of 7.

Ion

An ion is an atom or molecule that has lost or gained one or more electrons, resulting in a charge. For example, positively charged ions are called cations, while negatively charged ions are anions.

 Boiling Point

The boiling point is the temperature at which a liquid transforms into a gas. It is dependent on atmospheric pressure.

Melting Point 

The melting point is the temperature at which a solid melts into a liquid. For instance, pure substances melt at a constant temperature.

Covalent Bond

A covalent bond is a chemical bond that occurs when electrons are shared between atoms. Present in molecules, such as water (H2O) and carbon dioxide (CO2). 

Ionic Bond 

An ionic bond is a chemical bond that is formed when electrons are transferred from one atom to another. An example is the bond between sodium and chloride. In this case, one electron is transferred from the sodium atom to the chlorine atom. 

Periodic Table 

It is a table in which all known elements are arranged according to their atomic number, electron configurations, and chemical properties.

Atomic Number

 It is the count of protons in the nucleus of an atom. It determines the element.

Mass Number 

It is the sum of the number of protons and neutrons in the nucleus of an atom.

Isotope 

Isotopes are atoms of the same element containing the same number of protons but a different number of neutrons. For example, carbon-12 and carbon-14.

Valence Electrons 

These are electrons in the outer shell of an atom that participate in forming a bond. 

Concentration 

It is a quantity that relates to the amount of solute dissolved in a solution. It is represented in molarity (mol/L). 


Final Thought: 

These 20 definitions are the foundation of chemistry. Learn them, and you will be well-positioned to handle complex issues in examinations such as GCSE, A-levels, KCSE, and WAEC.

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