Difference Between Atom And Molecule

Atoms and Molecules are the basic building blocks of all matter around us. There are some fundamental differences between atoms and molecules but they are essential in understanding the behavior of the world around us. Initially, atoms were thought to be indestructible, i.e. we can not further break an atom into other parts. But later it was confirmed that atoms can be further divided into fundamental particles. Molecules are groups of one or more types of atoms that combined in a fixed ratio to form a compound.

The basic difference is that an atom is a single structure whereas, a molecule is a structure made of multiple atoms of the same or different kinds. In this article, we will learn about, Atoms, Molecules, their differences, and others in detail.

Atoms Definition

Atoms are the basic unit of matter, and they are the smallest particle that retains the chemical properties of an element. Atoms are composed of three types of particles:

• Protons
• Neutrons
• Electrons. 

The protons and neutrons are located in the nucleus, which is at the center of the atom. The electrons revolve in shells or energy levels surrounding the nucleus. Atoms are classified based on the number of protons in their nucleus, which is referred to as the atomic number. The property of elements varies by the number of protons in the atom’s nucleus.

Characteristics of an Atom

Various characteristics of an atom are,

• Atoms are the basic fundamental building blocks of all types of matter.
• Atoms are made up of even smaller particles called electrons, protons, and neutrons.
• In an atom protons and neutrons are inside its nucleus and electrons revolve around it.
• A proton in an atom is a positively charged species, an electron is a negatively charged species, and a neutron is a neutral species.
• As a whole, an atom is an electrically neutral species.
• An atom can donate and accept an electron.
• If an atom donates an electron it became positively charged called a cation.
• If an atom accepts an electron it became negatively charged called an anion.

Molecules Definition

Molecules are defined as the group of atoms chemically bonded together. Molecules can be composed of the same type of atom or different types of atoms. When atoms bond, they form a more stable structure called a molecule. Different types of chemical bonds can form between atoms, including covalent bonds, ionic bonds, and metallic bonds. In covalent bonding, atoms share electrons, while in ionic bonding, one atom transfers electrons to another atom. Metallic bonds are the special types of bonds generally formed between metals of d-blocks by the sharing of their electrons that differ from other types of bonds.

Characteristics of a Molecule

Various characteristics of a molecule are,

• All the compounds around us are made up of molecules.
• A molecule can exist in a solid, liquid, or gaseous state.
• A molecule is formed by combining two or more atoms in a fixed ratio.
• Various atoms in any molecule combined using different types of bonds
• For a molecule, the ratio of combining different atoms never changes.
• Some examples of the molecules are, H₂O (Water molecule), O₂ (Oxygen molecule), NH₃ (Ammonia molecule), etc.

The image added below shows a water molecule and a hydrogen atom, hydrogen atoms are highly unstable and generally, it did not exist in nature, it always reacts with other elements to form other stable compounds

Learn more about

• Molecular Mass
• Molecules and Compounds
• Molecular Weight Formula

Difference between Atoms and Molecules

The differences between atoms and molecules can be understood in the table discussed below,

Characteristics	Atoms	Molecules
Definition	Atoms are the smallest unit of an element that can exist either alone or in combination with other atoms	Molecules are formed when two or more atoms of different or the same elements chemically combine to form a stable particle.
Composition	Atoms are composed of protons, neutrons, and electrons	Molecules are composed of two or more atoms bonded together by covalent, ionic, or metallic bonds.
Size	Atoms are extremely small in size, with a diameter ranging from 0.1 to 0.5 nanometers	Molecules are comparatively larger in size than atoms, with a diameter ranging from 0.1 to 10 nanometers.
Shape	Spherical	Depending on the bond between the atoms it can be linear, triangular, etc.
Type	Atoms can be of the same element or different elements.	Molecules can only be formed by different or the same elements chemically combining.
Reactivity	Highly Reactive	Comparatively Less Reactive
Examples	Examples of atoms include Hydrogen(H), Carbon(C), Oxygen(O), etc.	Examples of molecules include Water (H2O), Carbon Dioxide (CO2), Glucose (C6H12O6), etc.

Read More,

• Composition of an Atom
• Discovery of Electrons
• Atomic Models

FAQs on Atoms and Molecules

What are Atoms?

An atom is the basic unit of all the matter in the universe. It is the fundamental block that combine to form all the matter around us. An atom can not be further divided into smaller part be general means. They are the smallest particles that retain all the property of the element.

What are Molecules?

Molecules consists of group of two or more than two atoms combined using various bonds to form all the different compounds we used. Various examples of molecules are,  H₂O (Water molecule), CO₂ (Carbon Dioxide molecule), etc.

What is Atom Vs Molecule?

The atom and the molecules are the basic building blocks that made up all the things around us, the basic difference between them is that atoms are the smallest part of an element that retain all its property whereas the molecule is the smallest part of an compound and all the molecules are formed by combining different types of atoms using bonds.

Can an Atom be Created?

Earlier scientists had the view that atoms are the basic particles and we can not create or destroy an atom but modern discoveries and experiment proves that atom are further made up of particles called electrons, protons and neutrons, and now scientist have prepared various atoms in the lab. Thus, we can say that atoms can be created.

Are Atoms and Molecules visible to the eyes?

Neither atom nor molecules are visible to human eyes as they are very very small and they can not be even seen through the microscopes. Using very strong electron microscope we can see the group of molecules but seeing individual atom and molecule is not possible yet.