Inorganic Master | Chapter-wise Hub 2026

Periodic Trends & OS

Atomic Size:Decreases cross series

Max OS:Mn (+7), Os (+8)

Min OS:Sc (+3)

Lanthanoid Contraction: Steady decrease in size of \(M^{3+}\) ions from Ce to Lu. Impact: Zr/Hf have identical sizes!

Magnetic & Catalytic

Formula:\(\mu = \sqrt{n(n+2)}\) BM

⭐ n = Number of unpaired electrons. More 'n' = More magnetic.

Catalysis: TM are good catalysts due to: 1. Variable OS, 2. Large Surface Area.

K2Cr2O7 & KMnO4 High Yields

K2Cr2O7: Chromite ore \(\to\) Sodium Chromate (Yellow) \(\to\) Sodium Dichromate (Orange) \(\to\) Potassium Dichromate.

KMnO4: Pyrolusite (\(MnO_2\)) \(\xrightarrow{KOH, O_2}\) \(K_2MnO_4\) (Green) \(\xrightarrow{H^+}\) \(KMnO_4\) (Purple).

IUPAC Naming Master

Example: \(K_3[Fe(CN)_6]\) \(\to\) Potassium hexacyanidoferrate(III).

Bonding (VBT & CFT)

Hybrid:\(sp^3, dsp^2, d^2sp^3\)

Spectrochemical Series: \(CO > CN^- > en > NH_3\) (Strong Field). Strong ligands cause pairing.

CFSE: \(\Delta_o\) (Octahedral) vs \(\Delta_t\) (Tetrahedral). \(\Delta_t = \frac{4}{9} \Delta_o\)

The Color Chart

Fe(3+)Yellow/Brown

Co(2+)Pink

Cr(3+)Violet/Green

Ti(3+)Purple

Crystal Clear: Ions with **Empty d** (\(d^0\)) or **Full d** (\(d^{10}\)) are Colorless (e.g., \(Sc^{3+}, Zn^{2+}\)).

Why? (Top Board Questions)

Q: Why is \(Cu^{2+}\) more stable than \(Cu^+\) in aqueous solution?
A: Due to much higher hydration enthalpy of \(Cu^{2+}\).

Q: Why do TM show variable oxidation states?
A: Because the energy gap between (n-1)d and ns orbitals is very small.

Q: Why do Coordination compounds show isomerism?
A: Due to different spatial arrangements of ligands (Geometrical/Optical).

NCERT Diagrams: d-orbital splitting patterns (Octahedral/Tetrahedral) are frequently asked.
Oxidation State: Coordination compounds me metal ki OS bracket me Roman numeral me (III, II) zaroor likho.
Precise Terms: "Poor shielding of f-electrons" is the keyword for Lanthanoid contraction.