Chemistry · Class 12 · p-Block Elements

p-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

Groups 13 to 18: trends, inert pair effect, important compounds (boranes, silicates, oxides, oxoacids, interhalogens, xenon compounds) and their structures.

Key ideas

p-Block Elements: what you must understand

Inert pair effect: lower oxidation states become stable down the group
Oxoacid acidity rises with oxidation state of the central atom
Structures of XeF₂, XeF₄, XeF₆ follow VSEPR
Diborane has 3-centre–2-electron bonds

Formula sheet

Must-know formulas for p-Block Elements

Oxoacids of P: H₃PO₂ (monobasic), H₃PO₃ (dibasic), H₃PO₄ (tribasic)
Bond angle order: NH₃ > PH₃ > AsH₃
Acidity of hydrogen halides: HI > HBr > HCl > HF
Thermal stability of hydrides decreases down a group

One-page formula sheet

Printable p-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 P–H bonds as acidic hydrogens
Wrong structures of interhalogens
Ignoring NCERT exceptions

For the exam

How this topic is asked in JEE

Appears in almost every JEE Main shift. Very high frequency and NCERT-based. Read the NCERT chapter twice and make a structures sheet.

Prerequisites: Chemical Bonding and Molecular Structure.

NCERT map

Where p-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 p-Block Elements	Group 15 Elements: Oxides of Nitrogen and Phosphorus; Group 16 Elements: Allotropic Forms of Sulphur and Oxoacids of Sulphur; Group 17 Elements: Interhalogen Compounds; Group 18 Elements: Compounds of Xenon and their Structures; Inert Pair Effect and Trends in p-Block Elements
Class 11	Chemistry Part II	The p-Block Elements	Group 13 Elements: Important Compounds of Boron (Borax, Boranes); Group 14 Elements: Allotropes of Carbon and Silicates; Anomalous Behaviour of First Element in Each Group

JEE Advanced level

A JEE Advanced-level example on p-Block Elements

Question. Consider the following statements about p-block elements and their compounds: (I) XeF₄ has a square planar geometry with two lone pairs on Xe in axial positions (II) In XeO₃, xenon is sp³ hybridized with one lone pair, giving a trigonal pyramidal shape (III) The inert pair effect explains why Tl⁺ is more stable than Tl³⁺ (IV) BF₃ is a stronger Lewis acid than BCl₃ because back bonding is more effective in BCl₃ How many of the above statements are correct?

Show solution

Statement I: XeF₄ has 4 bond pairs + 2 lone pairs = 6 electron domains. Hybridization is sp³d². Lone pairs occupy axial positions to minimize repulsion, giving square planar shape. CORRECT
Statement II: XeO₃ has 3 Xe=O bonds + 1 lone pair = 4 electron domains. Hybridization is sp³. Shape is trigonal pyramidal (similar to NH₃). CORRECT
Statement III: Inert pair effect means 6s² electrons in Tl are reluctant to bond due to poor shielding by inner d and f orbitals. So Tl⁺ (keeps 6s²) is more stable than Tl³⁺. CORRECT
Statement IV: Back bonding (pπ-pπ) is actually MORE effective in BF₃ because F(2p) and B(2p) orbitals have similar sizes. This makes BF₃ a WEAKER Lewis acid than BCl₃. INCORRECT
Count: Statements I, II, and III are correct. Statement IV has the reasoning backwards.

Answer: 3

This example was solved twice independently and both solutions agree.

Free lectures

Best free lectures for p-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.

P-BLOCK in One Shot: All Concepts & PYQs Covered | JEE Main & Advanced — JEE Wallah, 5:25:41
Jump to a subtopic (32)
- 00:00 Introduction
- 01:50 Topics to be covered
- 05:08 Metal, Non-Metal, Metalloid, Radioactive Element
- 13:40 Electronic Configuration
- 17:38 Atomic Radius, Ionisation Energy, Electronegativity & Electron Affinity
- 34:02 Inert Pair Effect
- 46:30 Application (Stability)
- 01:03:16 Questions
- 01:08:10 First Atom of Group & Questions
- 01:24:10 Bond Energy
- 01:31:50 Catenation Property
- 01:39:14 Allotropes of Carbon
- 02:08:00 Allotropes of Phosphorus
- 02:21:12 Allotropes of Sulphur
- 02:30:30 Physical Properties
- 02:38:12 Compounds of Boron
- 02:43:00 Break
- 02:59:50 Oxo - Acids
- 03:09:28 Acids of Nitrogen
- 03:11:58 Oxo - Acids of Sulphur & P
- 03:20:26 Acid having single & two Central Atom
- 03:41:40 Polythionic Acids & Anions
- 03:50:18 Questions
- 03:54:54 Nature of Oxides
- 04:08:12 Boiling Point
- 04:21:06 Hydrogen Containing Compounds
- 04:26:28 Back Bonding
- 04:49:25 Lewis Acidic Character
- 04:52:16 Bridge Bonding
- 05:02:52 Diborane
- 05:08:40 Table for Oxidising Power
- 05:23:38 Thank you
P BLOCK in One Shot for JEE Main and Advanced | JEE BRIEF | SAKSHI VORA — Vora Classes, 4:56:22

Practise

Where to practise for free

11 JEE Main 2026 PYQs on p-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 p-Block Elements important for JEE Main 2027?

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

What are the most important formulas in p-Block Elements?

Oxoacids of P: H₃PO₂ (monobasic), H₃PO₃ (dibasic), H₃PO₄ (tribasic); Bond angle order: NH₃ > PH₃ > AsH₃; Acidity of hydrogen halides: HI > HBr > HCl > HF.

How should I study p-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. Very high frequency and NCERT-based. Read the NCERT chapter twice and make a structures sheet.