Revision: Organic Chemistry >> Organic Compounds Chemistry (English Medium) ICSE Class 10 CISCE

The branch of chemistry that deals with compounds obtained from non-living sources or minerals, such as common salt, blue vitriol, and nitrates.

The branch of chemistry that deals with compounds originally derived from living organisms, such as sugar, starch, proteins, and acetic acid.

An atom or a group of atoms attached to an alkyl group, which takes part in most of the chemical reactions, is called a functional group or functional radical.

Organic compounds are the compounds of carbon.

When two or more compounds have a similar molecular formula but are different in the arrangement of carbon atoms in straight or branched chains, the compounds are referred to as chain isomers.

Compounds having the same molecular formula but different structural formulas are called isomers and the phenomenon is called isomerism.

The characteristic of the carbon atom, by virtue of which it forms four covalent bonds, is called the tetravalency of carbon.

Adsorption is the property due to which a substance absorbs gases, liquids and solids on its surface.

The process of the slow conversion of vegetable matter into carbon-rich substances is called carbonization.

Carbon possesses a unique property of combining with other carbon atoms to form long chains. This property is called catenation. The chains can be straight, branched or closed.

The self-linking property of atoms of an element to form very long straight or branched chains and cyclic rings is known as catenation. This property is shown by carbon whose small size and tetravalency helps it to form large structures by self-linking.

The property of self-linking of atoms of an element through covalent bonds in order to form straight chains, branched chains and cyclic chains of different sizes is known as catenation.

Saturated hydrocarbons (containing a single bond) are called ‘Alkanes’.

Hydrocarbons are compounds that 9re made up only of carbon and hydrogen atoms.

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The compounds which contain carbon and hydrogen as the only two elements are called hydrocarbons.

Saturated hydrocarbons are hydrocarbons in which the valencies of all atoms are satisfied by single bonds.

The unsaturated hydrocarbons containing a carbon-carbon double bond are called ‘Alkenes’.

The unsaturated hydrocarbons whose structures contain a carbon-carbon triple bond are called ‘Alkynes’.

The hydrocarbons that have double or triple covalent bonds between two adjacent carbon atoms are called unsaturated hydrocarbons.

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The carbon compounds having a double bond or triple bond between two carbon atoms are called unsaturated compounds. Ethene and ethyne are unsaturated hydrocarbons.

Cyclic compounds are organic compounds in which the carbon atoms are arranged in a ring or cyclic structure. When these rings contain only carbon atoms, they are called carbocyclic compounds, and their properties are similar to open-chain hydrocarbons.

The formula that shows how atoms of different elements are linked together in a molecule is known as a structural formula.

A structure that shows only the linking of carbon atoms in a molecule is called the carbon skeleton.

The functional group is defined as an atom or group of atoms joined in a specific manner which is responsible for the characteristic chemical properties of the organic compounds.

The same functional group substitutes for hydrogen in a carbon chain is called a homologous series.

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A homologous series is a group of organic compounds having  similar structure and similar chemical properties in which the successive compounds differ by a CH₂ group.

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The series of compounds formed by joining the same functional group in the place of a particular hydrogen atom on the chains having sequentially increasing length is called homologous series.

A series of compounds with similar chemical properties, in which members differ from one another by an additional CH₂ group, is called a homologous series.

Nomenclature is the system of assignment of names to organic compounds.

Compounds having the same molecular formula but different structural formula are known as Isomers and the phenomenon is known as Isomerism. (iso = same, meros = parts).

C_nH_2n+1COOH (or RCOOH)

• Hydrocarbons contain only carbon and hydrogen atoms and are the basic type of organic compounds.
• Saturated hydrocarbons have single bonds (e.g. methane, ethane, propane).
• Unsaturated hydrocarbons have double or triple bonds (e.g. ethene, ethyne).
• To draw structures, join the carbon atoms first, then add hydrogen atoms to complete 4 bonds per carbon.
• Ethene has a double bond, and ethyne has a triple bond between carbon atoms.

• The IUPAC system provides a unique, systematic way to name carbon compounds based on structure, replacing confusing common names.
• An IUPAC name has three parts: prefix, parent, and suffix, reflecting the carbon chain and functional group.
• The parent name is based on the longest carbon chain, and its ending changes to –ane, –ene, or –yne depending on the number of bonds.
• Functional groups are shown as prefixes or suffixes, and the chain is numbered to give them the lowest possible number.
• If the suffix begins with a vowel, the final ‘e’ in the parent alkane name is dropped (e.g., propane → propanone).

• Longest Chain: Choose the longest continuous carbon chain as the parent chain.
• Numbering: Number the chain so that branches or functional groups get the lowest possible numbers.
• Substituents: Name and position of alkyl groups are placed before the parent name (e.g., 3-methylpentane).
• Multiple Groups: Use prefixes like di-, tri-, etc., for repeated groups (e.g., 2,2-dimethylbutane).
• Alphabetical Order: Different substituents are listed alphabetically (e.g., 2-bromo-4-chlorohexane).

• Chain Isomerism: Same formula, different carbon chain structures (e.g., straight or branched).
• Position Isomerism: Same formula, functional group at different positions.
• Functional Isomerism: Same formula, different functional groups (e.g., alcohol vs ether).
• Metamerism (not in syllabus): Different alkyl groups on both sides of a functional group.
• More Carbons = More Isomers: The number of isomers increases with the number of carbon atoms.