JEE Main 2027 Chemistry — Exam Pattern & Marking
Chemistry is one of three subjects in JEE Main (Paper 1, B.E./B.Tech), carrying exactly the same weight as Physics and Mathematics. It is widely seen as the most scoring of the three: a large part of the paper rewards clean recall and quick single-step calculation, so accuracy and speed here can lift your whole percentile. Here is the pattern that has been stable in recent years and is expected to carry into 2027.
| Feature | Details |
|---|---|
| Mode | Computer-based test (CBT) |
| Subjects | Physics, Chemistry, Mathematics |
| Questions per subject | 25 (20 MCQ + 5 numerical-value), all compulsory |
| Total questions | 75 across the three subjects |
| Marks per subject | 100 (25 questions x 4 marks) |
| Total marks | 300 |
| Marking | +4 correct, -1 wrong (MCQ and numerical both) |
| Duration | 180 minutes (3 hours) |
Since 2025 all five numerical-value questions per subject are compulsory (the earlier "attempt any 5 of 10" option was removed). Every numerical answer is typed as a number, so there is negative marking on that section too — a change that rewards genuine problem-solving over guesswork. Always cross-check the official 2027 information bulletin (expected around October 2026) for any last-minute revision.
How Chemistry is Weighted — the Three Branches
Chemistry splits into three branches, and a balanced preparation treats all three:
- Physical Chemistry — the numerical heart of the paper (mole concept, thermodynamics, equilibrium, electrochemistry, kinetics, solutions). Most of the 5 numerical-value questions come from here.
- Inorganic Chemistry — high-yield and memory-driven, but with real reasoning (periodicity, bonding, coordination compounds, the p- and d-blocks). Coordination Compounds alone is one of the single most weighted units.
- Organic Chemistry — reasoning and mechanism heavy (general organic chemistry, hydrocarbons, and the oxygen/nitrogen/halogen families). Oxygen-containing compounds is typically the highest-weight unit of all.
The table below lists all 20 examinable units with their approximate share of the paper and a priority tag. Weightage bands are indicative (based on recent papers) and vary year to year.
| # | Unit | Branch | Weightage | Priority |
|---|---|---|---|---|
| 1 | Some Basic Concepts in Chemistry | Physical | 4-5% | Medium |
| 2 | Atomic Structure | Physical | 3-5% | Medium |
| 3 | Chemical Bonding & Molecular Structure | Inorganic | 3-4% | Medium |
| 4 | Chemical Thermodynamics | Physical | 6-7% | High |
| 5 | Solutions | Physical | 5-6% | High |
| 6 | Equilibrium | Physical | 5-6% | High |
| 7 | Redox Reactions & Electrochemistry | Physical | 5-6% | High |
| 8 | Chemical Kinetics | Physical | 4-6% | Medium |
| 9 | Classification of Elements & Periodicity | Inorganic | 4-5% | Medium |
| 10 | p-Block Elements | Inorganic | 3-5% | Medium |
| 11 | d- and f-Block Elements | Inorganic | 4-6% | Medium |
| 12 | Co-ordination Compounds | Inorganic | 8-9% | High |
| 13 | Purification & Characterisation of Organic Compounds | Organic | 1-2% | Low |
| 14 | Some Basic Principles of Organic Chemistry | Organic | 8-9% | High |
| 15 | Hydrocarbons | Organic | 3-5% | Medium |
| 16 | Organic Compounds Containing Halogens | Organic | 4-5% | Medium |
| 17 | Organic Compounds Containing Oxygen | Organic | 9-11% | High |
| 18 | Organic Compounds Containing Nitrogen | Organic | 3-5% | Medium |
| 19 | Biomolecules | Organic | 4-5% | Medium |
| 20 | Principles Related to Practical Chemistry | Practical | 2-3% | Low |
Physical Chemistry — Unit-wise Syllabus
Unit 1 — Some Basic Concepts in Chemistry. Matter and its nature; Dalton's atomic theory; concept of atom, molecule, element and compound; laws of chemical combination; atomic and molecular masses; mole concept and molar mass; percentage composition; empirical and molecular formulae; chemical equations and stoichiometry.
Unit 2 — Atomic Structure. Nature of electromagnetic radiation and the photoelectric effect; Bohr model of the hydrogen atom and its limitations; dual nature of matter, de Broglie relation, Heisenberg uncertainty principle; quantum-mechanical model — quantum numbers, shapes of s, p and d orbitals; Aufbau principle, Pauli exclusion principle, Hund's rule; electronic configuration of elements.
Unit 4 — Chemical Thermodynamics. System and surroundings; extensive and intensive properties; state functions; first law — internal energy, work, heat, enthalpy, heat capacity, Hess's law, enthalpies of reaction (formation, combustion, neutralisation, bond); second law — entropy, Gibbs energy, and the spontaneity criterion .
Unit 5 — Solutions. Methods of expressing concentration (molarity, molality, mole fraction, mass %); vapour pressure and Raoult's law; ideal and non-ideal solutions; colligative properties — relative lowering of vapour pressure, elevation of boiling point, depression of freezing point, osmotic pressure; determination of molecular mass; abnormal molecular mass and the Van't Hoff factor.
Unit 6 — Equilibrium. Physical and chemical equilibria; law of mass action, and ; Le Chatelier's principle; ionic equilibrium — acids and bases, Ostwald's dilution law, ionic product of water, pH, buffer solutions, common-ion effect, salt hydrolysis, and solubility product.
Unit 7 — Redox Reactions & Electrochemistry. Oxidation number and balancing of redox reactions; electrolytic and metallic conduction; conductance and molar conductivity; Kohlrausch's law; electrochemical cells, EMF, standard electrode potential, the Nernst equation and its link to Gibbs energy; dry cell, lead accumulator and fuel cells; Faraday's laws of electrolysis.
Unit 8 — Chemical Kinetics. Rate of reaction and the factors affecting it; order and molecularity; rate law and rate constant; integrated rate equations for zero- and first-order reactions; half-life; Arrhenius equation and activation energy; elementary idea of collision theory.
Inorganic Chemistry — Unit-wise Syllabus
Unit 3 — Chemical Bonding & Molecular Structure. Kössel-Lewis approach to bonding; ionic and covalent bonds; bond parameters; VSEPR theory and molecular geometry; valence bond theory and hybridization (, , , , ); molecular orbital theory for homonuclear diatomic molecules; hydrogen bonding.
Unit 9 — Classification of Elements & Periodicity in Properties. Modern periodic law and the present form of the periodic table; s-, p-, d- and f-block classification; periodic trends in atomic and ionic radii, ionization enthalpy, electron gain enthalpy, electronegativity and valency.
Unit 10 — p-Block Elements. Groups 13 to 18 — electronic configuration and general trends in physical and chemical properties down each group; anomalous behaviour of the first element; the more important compounds prescribed in the reduced NCERT syllabus.
Unit 11 — d- and f-Block Elements. Transition elements — general characteristics, variable oxidation states, colour, magnetic properties, catalytic behaviour, interstitial compounds and alloy formation; preparation and properties of potassium permanganate (KMnO4) and potassium dichromate (K2Cr2O7); lanthanoids — electronic configuration, oxidation states and lanthanoid contraction; a brief look at the actinoids.
Unit 12 — Co-ordination Compounds. Werner's theory; ligands, coordination number and denticity; IUPAC nomenclature of mononuclear complexes; isomerism (structural and stereo); bonding by valence bond theory and crystal field theory; colour and magnetic properties; importance and applications of coordination compounds.
Organic Chemistry — Unit-wise Syllabus
Unit 13 — Purification & Characterisation of Organic Compounds. Purification — crystallisation, sublimation, distillation, differential extraction and chromatography; qualitative detection of nitrogen, sulphur and halogens; quantitative estimation of carbon, hydrogen, nitrogen, halogens, sulphur and phosphorus; determination of empirical and molecular formulae.
Unit 14 — Some Basic Principles of Organic Chemistry. Tetravalency of carbon and shapes of organic molecules; classification and IUPAC nomenclature; isomerism (structural and stereoisomerism); covalent-bond fission (homolytic and heterolytic); electronic displacement effects — inductive, resonance (mesomeric), hyperconjugation and electromeric; reaction intermediates — carbocations, carbanions and free radicals; types of organic reactions — substitution, addition, elimination and rearrangement.
Unit 15 — Hydrocarbons. Alkanes — conformations, preparation and properties, halogenation; alkenes and alkynes — preparation, properties and addition reactions, Markovnikov's rule and the peroxide effect; aromatic hydrocarbons — benzene, aromaticity, electrophilic substitution and directive influence of substituents.
Unit 16 — Organic Compounds Containing Halogens. Haloalkanes and haloarenes — nomenclature, nature of the C-X bond, preparation, physical and chemical properties; substitution mechanisms SN1 and SN2; uses and environmental effects of chloroform, DDT and freons.
Unit 17 — Organic Compounds Containing Oxygen. Alcohols, phenols and ethers — preparation, properties and reactions; aldehydes and ketones — nucleophilic addition, aldol and Cannizzaro reactions; carboxylic acids — acidity, preparation and characteristic reactions. This is typically the single highest-weight unit in the paper.
Unit 18 — Organic Compounds Containing Nitrogen. Amines — classification, structure, basic character, preparation and reactions; diazonium salts — preparation and their importance in synthetic organic chemistry.
Unit 19 — Biomolecules. Carbohydrates — classification, monosaccharides, disaccharides and polysaccharides; proteins — amino acids, the peptide bond, structure levels and enzymes; vitamins; nucleic acids — DNA and RNA.
Practical Chemistry & How This Course Is Organized
Unit 20 — Principles Related to Practical Chemistry. Detection of extra elements (N, S, halogens) and functional groups in organic compounds; qualitative salt analysis of cations and anions; titrimetric (acid-base and redox) analysis; preparation of simple inorganic and organic compounds and the chemistry involved in their tests.
How the rest of this course works. From Chapter 2 onward, every chapter is one NTA unit and is pure practice. Each chapter gives you six graded question sets — two Easy, two Medium, one Hard, and one JEE Main previous-year-style set — each opening with a short concept recap and then 25 or more MCQs with full worked explanations. Physical-chemistry chapters lean into numerical problem-solving (including numerical-value questions that mirror Section B of the exam); Inorganic and Organic chapters build the multi-step reasoning — reactivity orders, mechanisms, structure-property links and nomenclature — that the tougher questions demand.
Chapter numbering follows the NTA unit order: Chapter 1 is this syllabus, Chapter 2 is Some Basic Concepts in Chemistry (Unit 1), Chapter 3 is Atomic Structure (Unit 2), and so on through Chapter 21 (Unit 20, Practical Chemistry). Work through the Easy sets first to lock in the fundamentals, use the Medium sets to build application speed, and treat the Hard and PYQ sets as your exam-readiness check.