Difference Between Atom and Molecule, Definition, Characteristics

Atom

An atom is called the fundamental unit of matter. It cannot be further divided into smaller parts and is made up of neutrons, electrons, and protons. Due to reactions between atoms, chemical reactions take place. Chemical reactions take place because of the reactions between atoms. The amalgamation of atoms along with each other forms a molecule. Generally, the number of protons and the number of electrons equal each other. Independent life may or may not be achievable inside an aqueous solution. Protons and neutrons form the nucleus in an atom. The electrons surround the nucleus and are placed on various levels of orbitals.

Characteristics of atoms

• An atom contains electrons, protons, and neutrons.
• The center of the atom is always a positive proton or positive charge.
• All atoms are electrically neutral
• Many theories were given to prove the charge of an atom.
• An atom of the same element has the same number of protons and neutrons.
• The size of an atom is shown by the size of its radius.

Example O, N, Fe

Molecule

A molecule is described as the merging of two or more same atoms or different atoms that are held together by various chemical bonds. A molecule is considered to be the smallest part of a substance and also it portrays every characteristic of that particular substance. When a molecule is broken down, it shows the features of the elements it is constituted of. Even when a pure substance is divided into its smaller parts, every part contains the characteristics of the main elements.

Characteristics of molecules

1. Molecules can be solid, liquid, or gas.
2. Molecules have a low melting point or high boiling point as compared to ionic compounds.
3. Molecules can either have low solubility or high solubility.
4. Molecules are poor conductors of heat and electricity.
5. In molecules, many solids attach and form a network crystal like a diamond.
6. Examples of molecules are H2O, N2, O3, CaO, etc.

Example: H2O, N2, NH3.

Difference between an atom and a molecule

1. Atom is the smallest particle of any element, whereas a molecule is the smallest particle of the compound.
2. Atoms may or may not present independently whereas molecules exist independently.
3. In atoms, molecules are made up of atoms whereas in molecules atoms form the molecule.
4. Atoms may or may not have matter properties whereas molecules have matter properties.
5. Examples of atoms are hydrogen, oxygen, nitrogen etc. Examples of molecules are H2 and O2 etc.
6. Atoms can be divided into many kinds, whereas molecules are of only two types - homoatomic molecules and heteroatomic.
7. Atoms don't have bonding whereas molecules have intermolecular forces and intramolecular forces.
8. Atoms are highly reactive except for noble gas, whereas molecules are less reactive.

Summary

Atoms are the fundamental unit of every matter that cannot be broken down further. It consists of electrons, protons, and neutrons. Whereas two or more similar or different kinds of atoms form a molecule. All the molecules, when broken down, show the characteristic properties of the substance.