Atoms and molecules are fundamental units in chemistry, and they have distinct characteristics. Here are five key differences between atoms and molecules:
Definition:
Atom:
Definition: An atom is the basic building block of matter and the smallest unit of an element that retains the chemical properties of that element. It consists of a nucleus containing protons and neutrons, with electrons orbiting the nucleus.
Molecule:
Definition: A molecule is a group of two or more atoms held together by chemical bonds. These atoms can be of the same or different elements. Molecules represent the smallest unit of a compound that retains its chemical properties.
Composition:
Atom:
Composition: An atom is composed of subatomic particles, including protons (positively charged), neutrons (neutral), and electrons (negatively charged).
Molecule:
Composition: A molecule is composed of two or more atoms chemically bonded together. These atoms can be of the same or different elements.
 Nature:
Atom:
Nature: Atoms are the basic units that make up elements. Each element is characterized by the unique number of protons in its atoms.
Molecule:
Nature: Molecules can be composed of atoms of the same element (e.g., oxygen gas – Oâ‚‚) or different elements (e.g., water – Hâ‚‚O).
 Chemical Properties:
Atom:
Chemical Properties: The chemical properties of an element are determined by the arrangement and number of electrons in its atoms. Atoms of the same element have similar chemical properties.
Molecule:
Chemical Properties: The chemical properties of a molecule are influenced by the types of atoms it contains and the way they are bonded. Different molecules exhibit different chemical properties.
 Independence:
Atom:
Independence: Atoms are independent and retain the properties of the element to which they belong. They can exist on their own or combine with other atoms to form molecules.
Molecule:
Independence: Molecules are independent units that can exist on their own. They can also combine with other molecules to form more complex structures.
In summary, atoms are the basic units of elements, composed of protons, neutrons, and electrons. Molecules, on the other hand, are groups of atoms chemically bonded together, and they represent the smallest units of compounds. The composition, nature, chemical properties, and independence of atoms and molecules distinguish these two fundamental entities in chemistry.