Chemistry · Class 12 · d- and f-Block Elements

d- and f-Block Elements for JEE

Everything you need for this topic on one page: the ideas, the formulas, the traps, and free lectures that explain it well.

Last updated: 26 October 2026

Direct answer

Transition elements: configuration, oxidation states, colour, magnetism, catalytic behaviour, KMnO₄ and K₂Cr₂O₇, and lanthanoids and actinoids.

Key ideas

d- and f-Block Elements: what you must understand

Variable oxidation states come from close (n−1)d and ns energies
Colour from d–d transitions; needs unpaired d electrons
Lanthanoid contraction makes Zr and Hf similar in size
KMnO₄ and K₂Cr₂O₇ are strong oxidising agents

Formula sheet

Must-know formulas for d- and f-Block Elements

Spin-only magnetic moment μ = √(n(n+2)) BM
MnO₄⁻ → Mn²⁺ in acid (5 e⁻); → MnO₂ in neutral (3 e⁻)
Cr₂O₇²⁻ → 2Cr³⁺ in acid (6 e⁻)
Sc³⁺ and Zn²⁺ are colourless (d⁰ and d¹⁰)

One-page formula sheet

Printable d- and f-Block Elements formula sheet: formulas, key ideas and traps on one page. Save it as a PDF for offline revision.

Avoid

Common mistakes students make

Counting unpaired electrons wrongly for ions
Forgetting Zn, Cd, Hg are not typical transition metals
Wrong electrons transferred by KMnO₄ in different media

For the exam

How this topic is asked in JEE

Appears in almost every JEE Main shift. Magnetic moment and oxidising-agent questions come almost every shift.

Prerequisites: Atomic Structure.

NCERT map

Where d- and f-Block Elements is in NCERT

Chapter names follow the current rationalised NCERT textbooks. Read these sections before solving PYQs.

Class	Book	Chapter	Sections JEE asks from
Class 12	Chemistry Part I	The d- and f-Block Elements	Electronic Configurations of the d-Block Elements; Oxidation States; Magnetic Properties; Some Important Compounds of Transition Elements (KMnO₄ and K₂Cr₂O₇); The Lanthanoids and Actinoids

JEE Advanced level

A JEE Advanced-level example on d- and f-Block Elements

Question. Potassium permanganate (KMnO₄) is used to titrate 25 mL of a solution containing Fe²⁺ ions in acidic medium. The titration requires 20 mL of 0.02 M KMnO₄ solution. (a) What is the oxidation state change of Mn during the reaction? (b) Calculate the molarity of Fe²⁺ in the original solution. (c) If the same Fe²⁺ solution is titrated with K₂Cr₂O₇ in acidic medium, what volume of 0.01 M K₂Cr₂O₇ would be required?

Show solution

In acidic medium, MnO₄⁻ (Mn in +7) is reduced to Mn²⁺ (Mn in +2). Oxidation state change = 7 − 2 = 5 units decrease.
Balanced equation: MnO₄⁻ + 8H⁺ + 5Fe²⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O. So 1 mol KMnO₄ reacts with 5 mol Fe²⁺.
Moles of KMnO₄ used = 0.02 × (20/1000) = 4 × 10⁻⁴ mol. Moles of Fe²⁺ = 5 × 4 × 10⁻⁴ = 2 × 10⁻³ mol.
Molarity of Fe²⁺ = (2 × 10⁻³)/(25 × 10⁻³) = 0.08 M.
For dichromate: Cr₂O₇²⁻ + 14H⁺ + 6Fe²⁺ → 2Cr³⁺ + 6Fe³⁺ + 7H₂O. So 1 mol K₂Cr₂O₇ reacts with 6 mol Fe²⁺.
Moles of K₂Cr₂O₇ needed = (2 × 10⁻³)/6 = 3.33 × 10⁻⁴ mol. Volume = (3.33 × 10⁻⁴)/0.01 = 0.0333 L = 33.3 mL.

Answer: (a) Mn changes from +7 to +2 (decrease of 5 units); (b) [Fe²⁺] = 0.08 M; (c) Volume of K₂Cr₂O₇ required = 33.3 mL

This example was solved twice independently and both solutions agree.

Free lectures

Best free lectures for d- and f-Block Elements

Full-chapter free lectures picked from YouTube search results by views, from established JEE channels (mostly in Hinglish). Use the subtopic list to jump straight to the part you need (timestamps come from each video's own chapter list). Watch one, then solve PYQs the same day.

D & F-BLOCK in One Shot: All Concepts & PYQs Covered | JEE Main & Advanced — JEE Wallah, 6:20:57
Jump to a subtopic (29)
- 00:00 Introduction
- 01:38 Topics to be covered
- 05:42 D-Block
- 34:45 Transition Elements & Variation of Oxidation State
- 59:09 Lanthanide Contraction & Its Effect
- 01:15:00 Ionization Energy
- 01:35:02 Melting & Boiling Point
- 01:48:32 Heat of Atomization
- 01:55:02 Reduction Potential
- 02:45:06 Interstitial Compounds
- 02:53:20 Catalytic Activity
- 03:07:46 Oxides
- 03:44:35 Break
- 04:02:00 Maganate & Permanganate
- 04:08:08 Table for Oxidising Power
- 04:21:15 Preparation of KMnO4
- 04:51:36 Neutral or Faintly Alkaline Solutions KMnO4
- 05:15:25 Oxo-anions of Cr
- 05:22:22 Preparation of Potassium Dichromate
- 05:32:20 Halides of d-block Elements
- 05:48:12 Lanthanoids
- 05:58:56 Oxidation State
- 06:03:02 Magnetic & Physical Properties
- 06:15:30 Uses of Lanthanides
- 06:23:48 Reactions of Lanthanides
- 06:25:46 Actinides
- 06:33:06 Oxidation state of Actinides
- 06:35:32 Questions
- 06:37:00 Thank you
D & F BLOCK in 1 Shot - All Concepts Covered || JEE Main & Advanced || Class 12 — Lakshya JEE, 4:54:29

Practise

Where to practise for free

10 JEE Main 2026 PYQs on d- and f-Block Elements, with solutions.
Read the chapter in NCERT textbooks (official, free), then solve its NCERT Exemplar (official, free) questions.
Chapter-wise past questions: JEE Main and Advanced PYQs and question bank.
Timed practice tests: NTA Abhyas practice tests (official, free) and our free mock tests.
See it move: interactive simulation.

FAQs

Frequently asked questions

Is d- and f-Block Elements important for JEE Main 2027?

Appears in almost every JEE Main shift. It is part of the official 'd- and f-Block Elements' unit in the JEE Main 2027 syllabus.

What are the most important formulas in d- and f-Block Elements?

Spin-only magnetic moment μ = √(n(n+2)) BM; MnO₄⁻ → Mn²⁺ in acid (5 e⁻); → MnO₂ in neutral (3 e⁻); Cr₂O₇²⁻ → 2Cr³⁺ in acid (6 e⁻).

How should I study d- and f-Block Elements for JEE?

Understand the key ideas from NCERT or one full lecture, learn the formula sheet, then solve 25–30 past JEE questions on the topic. Magnetic moment and oxidising-agent questions come almost every shift.