Difference Between Molecules and Compounds Last Updated : 23 Jul, 2025 Comments Improve Suggest changes Like Article Like Report Molecules are the smallest building blocks that form the matter around us. They are the simplest particles that carry the properties of matter. Molecules are joined together to form the Compound. A molecule is the smallest unit of matter formed by joining various atoms together whereas the compounds are the matter that we see around us. The water that we see around us is a compound that is made up of water molecules. The molecules of water are represented as H2O. Let's learn more about Molecules, Compounds, and Differences between Molecules and Compounds in this article. Table of Content What are Molecules?Examples of MoleculesWhat are Compounds?Types of CompoundsDifference Between Compounds and MoleculesWhat are Molecules?Molecules are made up of one or more atoms that are held together by covalent bonds. Atoms can be represented as circle shapes with a nucleus in the center, surrounded by one or more concentric circles representing the shells in which the electrons surrounding the nucleus of the atom are located, and markings indicating the electron. A molecule is the smallest unit of measurement that a substance can be divided into while still remaining the same substance. It is made up of two or more atoms that are chemically bonded together. Types of MoleculesMolecules can be categorised into various categories as, Monoatomic Molecule: Molecules containing only one atom is called monoatomic molecules. Examples are He (Helium), Ne (Neon), etc. Diatomic Molecule: Molecules containing two atoms are called diatomic molecules. Examples are O2 (Oxygen Gas), Cl2 (Chlorine Gas), etc. Polyatomic Molecule: Molecules containing more than two atoms are called polyatomic molecules. Examples are NH3 (Ammonia Gas), CO2 (Carbon Dioxide Gas), etc. Examples of MoleculesA molecule is the smallest unit of the compound which individually tells us about the components of the compound. Various examples of molecules are, H2O (Water)Water is the most fundamental molecule which we observe in our daily life. It has one oxygen and two hydrogen atom and its structure is discussed in the image below, NH3 (Ammonia)Ammonia is the first molecule which was mass-produced on the industrial level. It has one Nitrogen and three hydrogen atom and its structure is discussed in the image below, CH4 (Methane)Methane is the most important molecule to study the catenation property of carbon. It is the most basic organic compound. It has one Carbon and four hydrogen atom in its structure and its structure is discussed in the image below, What are Compounds?Compounds are a group of different atoms and different elements which unite together by a chemical bond. The chemical bond can be of three types, either covalent, ionic or metallic. Similarly, it is important to remember that all compounds are molecules but not all molecules are compounds. Moreover, we only categorize heteronuclear molecules as compounds. However, the same is not the case with homonuclear molecules. Remember that water's chemical formula is H2O. Water is composed of two hydrogen atoms and one oxygen atom in this note. When two different elements combine, a new substance known as water is formed. Compounds are substances formed by the combination of two or more types of elements. Atoms in a compound are chemically connected and thus cannot be easily separated. Similarly, carbon dioxide has the chemical formula CO2 and is made up of two elements: carbon and oxygen. Table salt (NaCl), chalk (CaCO3), and water are some other examples of compounds (H2O). Types of CompoundsCompounds are classified into two different categories namely, Molecular CompoundsIonic CompoundsMolecular CompoundsMolecular compounds are all the general compounds which represent the molecular formula of the compound. Examples of molecular compounds are water, carbon dioxide, etc. Ionic CompoundsCompounds formed by the electrovalent bond between two separate ions (Cations and Anions) are called Ionic compounds. Examples of ionic compounds are Sodium Chloride (NaCl), Potassium Chloride (KCl), Calcium Chloride (CaCl2), etc. Learn more about, Chemical Formula of Common Compounds Difference Between Compounds and MoleculesThe basic difference between the compounds and molecules is shown in the image added below, The table added below shows the differences between Molecules and Compounds. Differentiating PropertyMoleculeCompoundDefinitionMolecules are groups of two or more atoms that are held together by chemical bonds.Compounds are formed when two or more different elements are united chemically in a fixed proportion.RelatednessAll molecules are not considered compounds.All compounds are made up of molecules.StructureThey are groups of atoms that are bonded by a strong force.They are actual matter in their complete shape.Visibility Molecules are not seen with the naked eye.Compounds can be easily seen with the naked eye.StabilityMolecules can be stable or unstableCompounds are generally stable as it has a physical formExampleExamples of a molecule are Cl2, H2, etc.Examples of the compound are Sodium Hydroxide, Water, etc.Read More, Chemical FormulaTypes of Chemical BondsMolecular Mass Comment More infoAdvertise with us P prateek sharma 7 Follow Improve Article Tags : School Learning Class 9 Chemistry Chemistry-Class-9 Similar Reads Chemistry Chemistry is the scientific study of matter, its properties, composition, and interactions. It is often referred to as the central science because it connects and bridges the physical sciences, such as physics and biology. Understanding chemistry is crucial for comprehending the world around us, fro 6 min read Chapter 1 - Some Basic Concepts of ChemistryImportance of Chemistry in Everyday LifeImportance of Chemistry in Everyday Life: The scientific study of matter's properties and behavior is known as chemistry. It is a natural science that studies the elements that makeup matter, as well as the compounds, made up of atoms, molecules, and ions: their composition, structure, qualities, an 10 min read What is Matter ?The three basic states of matter are solid, liquid, and gaseous. All of the materials we come into contact with on a daily basis (from ice cream to chairs to water) are composed of matter. On the basis of intermolecular forces and particle arrangement, matter can be classified into three states: sol 9 min read Properties of MatterEvery matter has its own set of properties. Physical and chemical properties can be used to classify these properties. Physical properties are those that may be measured or observed without affecting the substance's identity or composition. Physical properties include odor, color, density, and so on 9 min read Measurement UncertaintyIn Chemistry, students often deal with experimental data and theoretical calculations. Most of the data is present in an extremely large number of quantum. This uncertainty in measurement is the range of possible values within which the true/real value of the measurement exists. There are practical 9 min read Laws of Chemical CombinationLaws of Chemical Combination are one of the most fundamental building blocks of the subject of chemistry. As in our surrounding different matter reacts with each other and form various kind of different substances. Laws of Chemical Combination are the collection of laws that explains how these subst 7 min read Dalton's Atomic TheoryIn the year 1808, the English scientist and chemist John Dalton proposed Dalton's atomic hypothesis, a scientific theory on the nature of matter. It asserted that all matter is made up of atoms, which are tiny, indivisible units. According to Dalton's atomic theory, all substances are made up of ato 8 min read Gram Atomic and Gram Molecular MassAvogadro's number is critical to understanding the structure of molecules as well as their interactions and combinations. e.g. because one atom of oxygen will combine with two atoms of hydrogen to form one molecule of water (H2O), one mole of oxygen (6.022 × 1023 of O atoms) will mix with two moles 7 min read Mole ConceptMole concept is the method used to express the amount of substance. This has been experimentally proving that one gram atom of any element, as well as one gram molecule of any substance, contains the same amount of entities. The experimentally decided number is found to be 6.022137 × 1023. After the 10 min read Percentage Composition - Definition, Formula, ExamplesDifferent constituent elements make up any chemical compound. In some chemical reaction calculations, you'll need to figure out how much of a certain element is in a specific compound. Or, in order to understand the contribution of a specific element in any of the stoichiometric calculations of a ch 5 min read Stoichiometry and Stoichiometric CalculationsJeremias Richter, a German chemist, was the first to create or discover the word Stoichiometry. The quantitative analysis of the reactants and products involved in a chemical reaction is known as chemical stoichiometry. The name "stoichiometry" comes from the Greek words "stoikhein" (element) and "m 7 min read Chapter 2 - Structure of AtomComposition of an AtomAtom is the smallest unit into which matter can be divided without the release of electrically charged particles. It is also the smallest unit of matter that has the characteristic properties of a chemical element. As such, the atom is the basic building block of matter. Atoms are extremely small, t 8 min read Atomic StructureAtomic structure is the structure of an atom that consists of a nucleus at the center containing neutrons and protons, while electrons revolve around the nucleus. Atoms are made up of a very tiny, positively charged nucleus that is surrounded by a cloud of negatively charged electrons. The earliest 15+ min read Developments Leading to Bohr's Model of AtomNeils Bohr, a scientist, expanded on Rutherford's model of the atom through his experiments. The dual nature of electromagnetic radiation was an important element in the development of Bohr's model. This indicates that radiations can have both wave-like and particle-like properties. Let's take a clo 6 min read Bohr's Model of the Hydrogen AtomThe Bohr model of the hydrogen atom was the first atomic model to successfully explain the atomic hydrogen radiation spectra. Niels Bohr proposed the atomic Hydrogen model in 1913. The Bohr Model of the Hydrogen Atom attempts to fill in some of the gaps left by Rutherford's model. It has a special p 9 min read Quantum Mechanical Atomic ModelSchrödinger used the electron's wave-particle duality to design and solve a difficult mathematical equation that precisely represented the behaviour of the electron in a hydrogen atom in 1926. The solution to Schrödinger's equation yielded the quantum mechanical model of the atom. The quantization o 8 min read Chapter 3 - Classification of Elements and Periodicity in PropertiesClassification of ElementsPeriodic categorization of elements is a way of grouping elements based on their characteristics, such as keeping elements that are similar in one group and the rest of the elements in the other. The elements are grouped in the long-form periodic table in order of their atomic numbers. The atomic nu 8 min read Periodic Classification of ElementsPeriodic Classification of Elements refers to the arrangement of elements on the basis of the periodic repetition of their properties. It means the elements which exhibit similar properties on a regular interval are placed in the same group. In this article, we will learn about, History of the Class 10 min read Modern Periodic LawAll matter in our environment is made up of basic units known as elements. Initially, only 31 chemical elements were discovered in 1800 and it was easier to study their chemical and other properties. However, as more and more elements were discovered due to technological advancements in science, it 6 min read 118 Elements and Their SymbolsEverything in the universe is composed of basic elements, and at their smallest level, these elements are atoms. There are a total of 118 elements in the modern periodic table out of which 98 are found in nature rest are chemically synthesized in laboratories. An atom of any element is composed of e 9 min read Electronic Configuration in Periods and GroupsElectronic Configuration is the arrangement of electrons in orbitals around an atomic nucleus. Electronic Configuration of a molecule refers to the distribution of electrons in various molecular orbitals. The number of electrons in bonding and antibonding molecular orbitals of a molecule or molecula 9 min read Electron ConfigurationElectron Configuration of an element tells us how electrons are filled inside various orbitals of the atom. The distribution of electrons inside various orbital of atoms is very useful in explaining various properties of the atoms and their combination with other atoms. The electron configuration of 8 min read S Block ElementsS-block elements are those elements in which the last electron is present in the s-orbital. In the periodic table. They reside in the first 2 columns. S-block consists of 14 elements that include, Hydrogen (H), Lithium (Li), Helium (He), Sodium (Na), Beryllium (Be), Potassium (K), Magnesium (Mg), Ru 9 min read Periodic Table TrendsArticle with the name "Periodic Table Trends" as the name suggests explores the trends and patterns in the property of elements while arranged in the modern-day periodic table. Scientists in the early days observed that while arranging the elements based on either atomic weight or atomic number, ele 13 min read Chapter 4 - Chemical Bonding and Molecular StructureChemical BondingChemical Bonding as the name suggests means the interaction of different elements or compounds which defines the properties of matter. Chemical bonds are formed when either at least one electron is lost to another atom, obtaining at least one electron from a different atom, or transferring one elect 12 min read Ionic BondIonic Bond is a bond that is formed by the electrostatic force of attraction between atoms. In an ionic bond, a complete transfer of electrons takes place in the process of bond formation. This bond is formed by the attracting force between the cations and the anions that are formed by the donating 8 min read Bond Parameters - Definition, Order, Angle, LengthSeveral bond parameters, such as bond length, bond angle, bond order, and bond energy, can be used to characterize covalent bonds (also known as bond enthalpy). These bond parameters provide information about the stability of a chemical compound as well as the strength of the chemical bonds that hol 7 min read VSEPR TheoryVSEPR Theory tells us about the basic structure of the molecules based on the force of repulsion between lone pair and bond pair of electrons. It states that any molecule arranged in such a structure minimizes the repulsion between the lone pair and bond pair of the molecule. Let's learn more about 9 min read Valence Bond TheoryValence bond theory (VBT) describes the formation of covalent bonds and the electronic structure of molecules. It assumes that electrons occupy atomic orbitals of individual atoms within a molecule, and that the electrons of one atom are attracted to the nucleus of another atom. VBT states that the 7 min read HybridizationThe concept of hybridization is defined as the process of combining two atomic orbitals to create a new type of hybridized orbitals. This intermixing typically results in the formation of hybrid orbitals with completely different energies, shapes, and so on. Hybridization is primarily carried out by 7 min read Molecular Orbital TheoryThe Molecular Orbital Theory is a chemical bonding theory developed at the turn of the twentieth century by F. R. Hund and R. S. Mulliken to explain the structure and properties of various molecules. The valence-bond theory failed to adequately explain how certain molecules, such as resonance-stabil 7 min read Hydrogen BondingIn chemistry, a hydrogen bond is an electrostatic force of attraction between a hydrogen atom and another electronegative atom. It is a special type of dipole-dipole force. Hydrogen bonding is the phenomenon of the formation of Hydrogen Bonds. H Bonds are stronger than any dipole-dipole bonds but we 13 min read Chapter 5 - ThermodynamicsBasics Concepts of ThermodynamicsThermodynamics is concerned with the ideas of heat and temperature, as well as the exchange of heat and other forms of energy. The branch of science that is known as thermodynamics is related to the study of various kinds of energy and its interconversion. The behaviour of these quantities is govern 12 min read Applications of First Law of ThermodynamicsEnergy, like matter, is always conserved, which means that it cannot be created or destroyed, but it can be converted from one form to another. Internal energy is a thermodynamic attribute of a system that refers to the energy associated with the system's molecules and comprises both kinetic and pot 8 min read Internal Energy as a State of SystemThe various forms of energy are interconnected, and they can be converted from one form to another under certain conditions. The field of science known as thermodynamics is related to the study of various kinds of energy and its conversion. In thermodynamics, the system refers to the part of the uni 8 min read Enthalpy Change of a ReactionThe study of thermodynamics is the study of systems that are too large to be extrapolated by mechanics alone. For many generations, thermodynamics was vaguely understood, and many of the results were determined only experimentally. Some of the results posed great theoretical challenges for physicist 9 min read Enthalpies for Different Types of ReactionsThermodynamics is a field of physics that studies the relationship between heat, work, and temperature, as well as their relationships with energy, entropy, and the physical properties of matter and radiation. The four principles of thermodynamics regulate the behaviour of these quantities, which pr 10 min read What is Spontaneity? - Definition, Types, Gibbs EnergyThermodynamics is a discipline of physics that studies heat, work, and temperature, as well as their relationships with energy, radiation, and matter's physical characteristics. The four principles of thermodynamics regulate the behaviour of these quantities, which provide a quantitative description 7 min read Gibbs Energy Change and EquilibriumEnergy can take many forms, including kinetic energy produced by an object's movement, potential energy produced by an object's position, heat energy transferred from one object to another due to a temperature difference, radiant energy associated with sunlight, the electrical energy produced in gal 10 min read Chapter 6 - EquilibriumEquilibrium in Physical ProcessesEquilibrium exists in physical processes, just as it does in chemical reactions. The equilibrium that arises between different states or phases of a substance, such as solid, liquid, and gas, is referred to as this. Let's take a closer look at how equilibrium works in physical processes. Substances 11 min read Equilibrium in Chemical ProcessesChemical equilibrium is the state of a system in which the reactant and product concentrations do not change over time and the system's attributes do not change further. Reactions take place in both forward and reverse directions. When the rates of the forward and reverse reactions are similar in su 7 min read Law of Chemical Equilibrium and Equilibrium ConstantDuring a chemical process, chemical equilibrium refers to the state in which the concentrations of both reactants and products have no tendency to fluctuate over time. When the forward and reverse reaction rates are equal, a chemical reaction is said to be in chemical equilibrium. The state is known 8 min read Difference between Homogeneous and Heterogeneous EquilibriaIn our daily lives, we witness several reactions such as iron rusting, paper burning, curd sourness, ozone generation, and so on. Many of these reactions require the presence of components in distinct phases, such as solid iron reacting with gaseous oxygen to generate solid iron oxide, which we call 7 min read Applications of Equilibrium ConstantsWhen a chemical process reaches equilibrium, the equilibrium constant (usually represented by the symbol K) provides information on the relationship between the products and reactants. For example, the equilibrium constant of concentration (denoted by Kc) of a chemical reaction at equilibrium can be 6 min read What is the Relation between Equilibrium Constant, Reaction Quotient and Gibbs Energy?A scientist was observing a reaction and at a certain point and found the concentration of reactant is equal to the concentration of product and after some time and observed color of reactant is changing, the scientist found concentration of products is greater than the concentration of reactants, f 8 min read Factors Affecting Chemical EquilibriumWhen the concentrations of reactants and products do not change over time, they are said to be in a state of equilibrium. The stability of certain observable attributes such as pressure, density, and so on can be used to identify this state. Physical equilibrium is the equilibrium set up in physical 8 min read Ionic EquilibriumReactants and products coexist in equilibrium, therefore reactant conversion to product is never greater than 100%. Equilibrium reactions may entail the breakdown of a covalent (non-polar) reactant or the ionisation of ionic compounds in polar solvents into their ions. This part will teach us about 5 min read Acids, Bases and SaltsAcids, Bases, and Salts are the main chemical compounds that exist in our surroundings. Acids, Bases, and Salts are compounds that occur naturally and can also be created artificially. They are found in various substances including our food. Vinegar or acetic acid is used as a food preservative. Cit 15+ min read Ionization of Acids and BasesIonization of a compound in Chemistry is the process by which neutral molecules are divided into charged ions in a solution. According to the Arrhenius Theory, acids are substances that dissociate in an aqueous medium to produce hydrogen ions, H+ ions, and bases are substances that dissociate in an 6 min read Buffer SolutionBuffer Solution is a special aqueous solution that resists the change in its pH when some quantity of acid and Base is added. Many fluids, such as blood, have specific pH values of 7.14, and variations in these values indicate that the body is malfunctioning. The change in pH of Buffer Solutions on 10 min read Solubility EquilibriaThe word "solubility product" refers to inexpensively soluble salts. It is the greatest product of the molar concentration of the ions (raised to their appropriate powers) produced by compound dissociation. The solubility product is constant at any given temperature. The lower the solubility product 5 min read Chapter 7 - Redox ReactionsRedox ReactionsRedox Reactions are oxidation and reduction reactions that happen simultaneously in a chemical reaction and in this, the reactant undergoes a change in its oxidation state. Redox stands for Reduction - Oxidation. Redox reaction is a common term used in both Chemistry and Biology. They are a certain 14 min read Redox Reactions in terms of Electron TransferA variety of chemical and biological reactions like burning of different types of fuels (wood, kerosene, coal, LPG, petrol, diesel), digestion of food in animals, photosynthesis by plants, extraction of aluminum from alumina, electricity generation from batteries or cell, rusting of iron fall in the 4 min read Oxidation Number | Definition, How To Find, ExamplesOxidation number is defined as the total number of electrons that an atom either gains or loses to form a chemical bond with another atom. Let's learn about oxidation number in detail, including its rules and steps to calculate it with the help of examples. Table of Content Oxidation Number Definit 13 min read Redox Reactions and Electrode ProcessesElectrode Potential and Standard Electrode Potential are key concepts in the field of electrochemistry which is the branch of chemistry that deals with relationships between electric potential differences and observable chemical change. Electrode Potential is also used extensively in the development 8 min read Chapter 8 - Organic Chemistry – Some Basic Principles and TechniquesOrganic Chemistry - Some Basic Principles and TechniquesOrganic Chemistry is the branch of science that deals with the study of the structure, properties, composition, and reaction of hydrocarbons and their derivatives. It is the science of organic compounds and it started about 200-225 years ago. It is the branch of chemistry that deals with the scienti 10 min read What is Catenation and Tetravalency?Carbon is a non-metallic element. Carbon is found in very small amounts in the earth's crust and atmosphere. Even though there is just a limited amount of carbon in nature, the carbon atom is extremely important in many aspects of life. We, as well as all living things, plants, and animals, are made 6 min read Structural Representations of Organic CompoundsOrganic compounds are the most widely used compounds in chemistry as well as in everyday life. Any organic compound has only one chemical formula but can be represented on paper using various structural formulas as per our convenience and the complexity of the structure of the compound. In this arti 5 min read Classification of Organic CompoundsOrganic compounds are defined as chemical compounds which contain carbon atoms linked with other elements through simple covalent bonds. These elements could be connected by single covalent bonds, double covalent bonds, or triple covalent bonds. In other words, we can say that all organic compounds 12 min read IUPAC Nomenclature of Organic CompoundsOrganic Compounds are those which have Carbon-Hydrogen or Carbon-Carbon bonds. Chemistry is studied under three branches Organic, Inorganic, and Physical Chemistry with each dealing with different types of topics. For this article, we will focus on Organic Chemistry which is the study of carbon and 13 min read IsomerismIsomerism refers to the phenomenon where two or more compounds have the same molecular formula but different structural arrangements or spatial orientations, resulting in distinct chemical properties. These compounds with the same formula but different structures are called isomers. Let's learn abou 6 min read Fundamental Concepts in Organic Reaction MechanismOrganic chemistry is the chemistry of carbon compounds except for oxides of carbon and metal carbonates. Carbon has the uncommon characteristic of forming strong bonds with many other elements, particularly with other carbon atoms, to form chains and rings, giving rise to millions of organic molecul 15+ min read Purification of Organic CompoundsOrganic chemistry is the study of carbon-containing molecules' structure, characteristics, content, reactions, and production. The majority of organic compounds contain carbon and hydrogen, but they may also contain a variety of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, 5 min read Qualitative Analysis of Organic CompoundsOrganic chemistry is a branch of science that studies the structure, properties, and interactions of organic compounds having covalent carbon bonds. By examining their structure, their structural formula can be derived. To better understand their behavior, physical and chemical properties, as well a 10 min read What is Quantitative Analysis?Quantitative analysis is one of the important processes in chemistry. It is used to determine mass percent i.e. to determine the mass of every element present. It can also be defined as a method used to determine the number of chemicals in a sample. The mass per cent is important to find the molecul 9 min read Chapter 9 - HydrocarbonsWhat are Hydrocarbons?Alkanes and cycloalkanes are hydrocarbons with no double or triple bond functional groups, depending on whether the carbon atoms of the molecule are organized in chains or rings. Alkenes and alkynes are hydrocarbons with double or triple bonds, respectively. The following mentioned are the rules for 11 min read Classification of HydrocarbonsOrganic chemistry is the branch of chemistry that deals with the reactions, structures, and properties (physical and chemical) of organic compounds that contain carbon atoms and covalent bonds (a chemical bond that involves sharing of electrons between atoms). Any group of organic chemical compounds 10 min read Alkanes - Definition, Nomenclature, Preparation, PropertiesIn natural science, a hydrocarbon is a natural atom comprising completely hydrogen and carbon. Hydrocarbons are an illustration of gathering 14 hydrides. Hydrocarbons are dreary and hydrophobic, with a slight scent. As a result of their diverse compound designs, it's difficult, to sum up anymore. Th 7 min read Alkenes - Definition, Nomenclature, Preparation, PropertiesIn organic chemistry, a hydrocarbon is an organic molecule consisting entirely of hydrogen and carbon. Hydrocarbons are an example of group 14 hydrides. Hydrocarbons are colourless and hydrophobic, with a slight odour. Because of their different chemical structures, it's hard to generalise anymore. 6 min read Alkynes - Definition, Structure, Preparation, PropertiesA hydrocarbon is an organic molecule made completely of hydrogen and carbon in organic chemistry. Hydrocarbons are an example of hydrides in group 14. Hydrocarbons are colourless, hydrophobic, and have just a faint odour. It's impossible to generalise further due to their varied molecular architectu 8 min read Aromatic CompoundsAromatic Hydrocarbons are alkyl, alkenyl, and alkynyl derivatives of cyclic hydrocarbons which include one or more benzene rings fused or isolated in their molecules and cyclic hydrocarbons are those hydrocarbons in which carbon atoms are connected to form a complete cycle or closed ring structure. 9 min read Like