IIT-JEE MAINS 2027 cheat sheet for Inorganic Chemistry! 📱 Practice 1 Lakh+ PYQs on ExamBhai.com! - Free Study Material

Inorganic Chemistry Revision & Concept Summary

Mastering Inorganic Chemistry for IIT-JEE Mains 2027 requires a clear understanding of periodic trends, bonding theories, and coordination compounds. Below is a structured summary of core concepts and formulas essential for rapid revision.

1. Periodic Table & Periodic Properties

Periodic trends govern chemical reactivity. Effective nuclear charge (\(Z_{eff}\)) increases across a period and decreases down a group, influencing atomic radii, ionization enthalpy, and electron gain enthalpy.

• Ionization Enthalpy (IE): Order of first ionization energy across Period 2: \(Li < B < Be < C < O < N < F < Ne\). Note the anomaly where \(IE_1(Be) > IE_1(B)\) due to fully filled \(2s^2\) subshell stability, and \(IE_1(N) > IE_1(O)\) due to half-filled \(2p^3\) configuration.
• Electronegativity: Calculated using Pauling's scale: \(|X_A - X_B| = 0.208 \times \sqrt{E_{d(A-B)} - \sqrt{E_{d(A-A)} \times E_{d(B-B)}}}\), where bond dissociation energies \(E_d\) are in \(kcal/mol\).

2. Chemical Bonding & Molecular Structure

Predicting molecular shapes, hybridization, and magnetic properties is central to JEE problem-solving.

• Fajans' Rules: Covalent character in an ionic bond increases with smaller cation size, larger anion size, and higher charge on either ion.
• Bond Order (Molecular Orbital Theory): \(Bond\ Order = \frac{N_b - N_a}{2}\). For instance, superoxide ion \(O_2^-\)$ incorporates 17 electrons, giving a bond order of \(1.5\) and displaying paramagnetic behavior.
• Representative Structure: Consider the spatial arrangement of sulfuric acid ($H_2SO_4$):

```smiles O=S(=O)(O)O ```

3. Coordination Compounds

Coordination chemistry focuses on isomerism, Crystal Field Theory (CFT), and bonding theories.

• Crystal Field Splitting Energy (CFSE): For octahedral complexes (\(\Delta_o\)), CFSE is given by: \(CFSE = (-0.4 \times n_{t_{2g}} + 0.6 \times n_{e_g}) \Delta_o + P\), where \(P\) is the pairing energy.
• Magnetic Moment: Spin-only magnetic moment formula: \(\mu = \sqrt{n(n+2)}\ BM\), where \(n\) is the number of unpaired electrons.
• Key Reaction: Formation of Prussian blue complex: \(4Fe^{3+} + 3[Fe(CN)_6]^{4-} \to Fe_4[Fe(CN)_6]_3\).