Molecules. Structure and types

A molecule is the smallest unit of a substance that still retains the chemical and physical properties of that substance. It is composed of two or more atoms that are bonded together by chemical bonds to form a stable structure.

The structure of a molecule can be linear, branched or three-dimensional, depending on how the atoms are bonded together. The arrangement of atoms in a molecule determines its physical and chemical properties, such as its melting point, boiling point, solubility, reactivity and polarity.

There are different types of molecules that can be classified according to their chemical composition and function.

Organic molecules. They are mainly composed of carbon, hydrogen and oxygen atoms, although they can also contain other elements such as nitrogen, phosphorus, sulfur and halogens. Examples of organic molecules include carbohydrates, lipids, proteins and nucleic acids.

Inorganic molecules. These are molecules that do not contain carbon and are generally simpler in structure than organic molecules. Examples of inorganic molecules include water (H₂O), carbon dioxide (CO₂), salts and minerals.

Biomolecules. These are molecules found in living things that perform essential functions in biological processes. Biomolecules include proteins, carbohydrates, lipids and nucleic acids.

Simple molecules. These are molecules composed of only one type of atom. Examples of simple molecules include oxygen (O₂), nitrogen (N₂) and chlorine (Cl₂).

Complex molecules. These are molecules composed of two or more types of atoms. Examples of complex molecules include glucose (C₆H₁₂O₆), hydrochloric acid (HCl) and ammonia (NH₃).