Inorganic Chemistry PYQs for NEET: 15-Year Trends and Concepts

Preparing for Inorganic Chemistry often feels challenging because students try to memorise isolated facts instead of understanding fundamental patterns. Working through Inorganic Chemistry PYQs for NEET allows you to recognise recurring question patterns and focus only on what the latest examination framework requires. The dedicated faculty at Physics Wallah focuses on breaking down past papers into manageable, high-yield learning modules to help aspirants build exam-day accuracy.

Inorganic Chemistry carries significant weight in the paper, and solving past papers clears confusion around anomalous properties, shielding effects, and coordination geometries.

Why Inorganic Chemistry PYQs Matter for NEET 2027

Solving past papers gives you immediate clarity on how theoretical lines from textbooks convert into multiple-choice questions. Regular practice shows which chapters have higher concept density and helps you eliminate wrong options quickly during the exam.

Practising past 15 years' questions prevents you from studying obsolete syllabus portions, such as detailed preparation of silicates or complex oxoacids. By targeting authentic patterns, you save time and improve both your problem-solving speed and accuracy.

Periodic Table and Periodicity: Key PYQ Concepts

The periodic table serves as the backbone of all chemical trends, including atomic sizes, ionization energies, and ionic radii comparisons. The following points highlight essential patterns frequently tested in the medical entrance exam:

• Atomic and Ionic Radii in Isoelectronic Series: For species with the same number of electrons (such as Al3+, Mg2+, Na+, F-, O2-, N3-), size decreases as the positive nuclear charge increases. More positive charge pulls electrons closer, making Al3+ the smallest and N3- the largest among 10-electron ions.

• First Ionisation Enthalpy Anomalies: Ionisation energy does not increase smoothly from left to right. Penetration effects make beryllium (2s2) higher than boron (2s2 2p1). Similarly, half-filled stability gives nitrogen (2p3) a higher first ionisation enthalpy than oxygen (2p4).

• Melting Points of Group 1 and Group 3 Elements: Gallium and caesium both possess notably low melting points, contrary to common misunderstandings about metal lattice strengths.

• IUPAC Nomenclature for Elements with Z > 100: Names are formed directly from numerical roots (0 = nil, 1 = un, 2 = bi, 3 = tri, 4 = quad, 5 = pent, 6 = hex, 7 = sept, 8 = oct, 9 = enn) ending with "ium". For instance, element 101 is Unnilunium (Mendelevium), element 106 is Unnilhexium (Seaborgium), and element 111 is Unununium (Roentgenium).

Chemical Bonding and Molecular Structure: PYQ Trends

Questions on chemical bonding test your understanding of molecular shapes, dipole cancellation, and molecular orbital filling.

• Valence Shell Electron Pair Repulsion (VSEPR): The shape of a molecule depends strictly on sigma bonds and lone pairs on the central atom. Methane (CH4) has zero lone pairs and a bond angle of 109.5 degrees. Ammonia (NH3) has one lone pair, compressing the angle to roughly 107 degrees. Water (H2O) has two lone pairs, which squeeze the bond angle down to 104.5 degrees due to stronger lone pair-lone pair repulsions.

• Dipole Moments and Molecular Symmetry: Symmetrical molecules with identical surrounding atoms have zero dipole moments because individual bond vectors cancel out. Examples include BF3 (trigonal planar), BeF2 (linear), and CCl4 (tetrahedral). Conversely, NH3 has a larger dipole moment than NF3 because in NH3, the N-H bond dipoles reinforce the lone pair dipole, whereas in NF3, the highly electronegative fluorine atoms pull electron density in the opposite direction.

• Molecular Orbital Theory (MOT): Molecules with 14 electrons (like N2 and CO) have a bond order of 3. Molecules with 16 electrons (like O2) have a bond order of 2 and exhibit paramagnetism due to two unpaired electrons in antibonding pi orbitals. Diatomic carbon (C2) contains 12 electrons, and its double bond consists entirely of two pi bonds formed from electrons in pi 2px and pi 2py bonding orbitals.

• Bond Order and Stability: A bond order of zero (as in Be2) indicates that the molecule is unstable and cannot exist under standard conditions.

p-Block Elements Important Concepts and Syllabus Focus

Recent exam updates have streamlined the p-block syllabus, shifting focus away from industrial preparations and towards fundamental periodic group trends.

• Inert Pair Effect: As you move down groups 13, 14, and 15, the outer s-electrons become less available for bonding due to poor shielding by inner d and f orbitals. Consequently, lower oxidation states become more stable. In group 14, Sn2+ acts as a reducing agent because Sn4+ is more stable, whereas Pb4+ acts as an oxidising agent because Pb2+ is far more stable.

• Covalency Limitations: Second-period elements like boron cannot expand their octet due to the absence of vacant d orbitals, limiting their maximum covalency to 4. Therefore, species like BF6 3- cannot form.

• Steric Hindrance in Silicon Halides: Silicon forms stable SiF6 2- complexes because fluorine is small. However, large halide ions like chlorine cause severe steric repulsion, preventing the formation of SiCl6 2-.

• Hydrides of Group 15, 16, and 17: Down each group, bond length increases, causing bond dissociation enthalpy and thermal stability to decrease. As a result, acidic strength increases down the group from HF to HI, and from H2O to H2Te.

• Anomalous Boiling Points: Water (H2O) and hydrogen fluoride (HF) exhibit unusually high boiling points within their respective groups because of strong intermolecular hydrogen bonding.

Coordination Compounds and Isomerism: High-Yield Points

Coordination chemistry questions frequently cover crystal field splitting, magnetic properties, and isomerism.

• Homoleptic versus Heteroleptic Complexes: Complexes containing only one type of ligand (such as [Co(NH3)6]3+) are homoleptic, whereas complexes with multiple ligand types (such as [Co(NH3)4Cl2]+) are heteroleptic.

• Chelate Effect: Polydentate ligands like ethylenediamine (en) and oxalate (C2O4 2-) form stable ring structures with metal ions. Complexes with chelate rings show significantly higher thermodynamic stability than those with simple monodentate ligands.

• EDTA Coordination: Ethylene diamine tetraacetate (EDTA 4-) is a hexadentate ligand possessing two nitrogen and four oxygen donor atoms.

• Structural and Optical Isomerism: Linkage isomerism occurs when ambidentate ligands (such as NO2- versus ONO-) bind through different donor atoms. Octahedral complexes of the type [M(AA)2B2], such as [Co(en)2Cl2]+, exist as cis and trans geometrical isomers. The cis isomer lacks a plane of symmetry and is optically active, producing non-superimposable mirror images, while the trans isomer is optically inactive.

• Synergic Bonding in Metal Carbonyls: In metal carbonyls, the ligand donates electron density through a sigma bond to the metal, while the metal back-donates d-orbital electron density into the empty antibonding pi orbital of carbon monoxide. This strengthens the metal-carbon bond while lengthening and weakening the carbon-oxygen bond.

d-Block and f-Block Elements: PYQs Highlights

The d and f-block sections test electronic configurations, magnetic moments, and lanthanoid contraction principles.

• Spin-Only Magnetic Moment: Calculated using the relation square root of [n(n + 2)] Bohr Magnetons, where n represents the number of unpaired d-electrons. A d4 ion (such as Cr2+) or a d6 high-spin ion (such as Fe2+) has 4 unpaired electrons, yielding a magnetic moment of 4.90 BM. A d5 high-spin ion (such as Mn2+ or Fe3+) has 5 unpaired electrons, giving 5.92 BM.

• Lanthanoid Contraction: The poor shielding effect of 4f electrons causes a steady decrease in atomic and ionic radii across the series. Consequently, pairs like zirconium (Zr) and hafnium (Hf) possess almost identical atomic radii and similar chemical behaviour.

• Stability of Cu2+ versus Cu+ in Water: Although Cu+ has a completely filled d10 electronic configuration, Cu2+ is more stable in aqueous solution because its high charge density gives it a much more negative hydration enthalpy, easily compensating for the second ionisation energy.

• Oxidation and Catalytic Behaviour: Transition metals show variable oxidation states because their (n-1)d and ns energy levels lie close together, allowing them to participate in multiple redox steps during catalytic processes.

Important Questions Asked in the Last 15 Years: Inorganic Chemistry PYQs

Question 1

Arrange the following elements in increasing order of first ionisation enthalpy: Li, Be, B, C, N.

Choose the correct answer from the options given below:

(A) Li < Be < C < B < N

(B) Li < Be < N < B < C

(C) Li < Be < B < C < N

(D) Li < B < Be < C < N

Question 2

Which of the following orders of ionic radii is correctly represented?

(A) Na⁺ > F⁻ > O²⁻

(B) O²⁻ > F⁻ > Na⁺

(C) Al³⁺ > Mg²⁺ > N³⁻

(D) H⁻ > H⁺ > H

Question 3

Be²⁺ is isoelectronic with which of the following ions?

(A) Li⁺

(B) Na⁺

(C) Mg²⁺

(D) H⁺

Question 4

Identify the correct answer.

(A) The dipole moment of NF₃ is greater than that of NH₃.

(B) Three canonical forms can be drawn for the CO₃²⁻ ion.

(C) Three resonance structures can be drawn for ozone.

(D) BF₃ has a non-zero dipole moment.

Question 5

Which one of the following pairs of species has the same bond order?

(A) N₂, O₂⁻

(B) CO, NO

(C) O₂, NO⁺

(D) CN⁻, CO

Question 6

Identify the incorrect statement related to PCl₅ from the following:

(A) The three equatorial P–Cl bonds make an angle of 120° with each other.

(B) The two axial P–Cl bonds make an angle of 180° with each other.

(C) The axial P–Cl bonds are longer than the equatorial P–Cl bonds.

(D) The PCl₅ molecule is non-reactive.

Question 7

The correct geometry and hybridisation for XeF₄ are:

(A) Octahedral, sp³d²

(B) Trigonal bipyramidal, sp³d

(C) Planar triangle, sp³d³

(D) Square planar, sp³d²

High-Yield Inorganic Chemistry Concepts: Quick Revision

The table outlines core topics, recurring themes, and practical memory rules derived from the last 15 years of exam papers.

Mastering Inorganic Chemistry comes down to identifying recurring patterns across periodic trends, bonding geometries, and coordination complexes. Regular revision with authentic past papers ensures you spend your study hours on topics that truly appear on exam day. For thorough concept revision and practice tests tailored to competitive medical exams, explore the structured resources and mentoring available through PW NEET Coaching programs.

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