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Edexcel A Level Chemistry

Shapes of Molecules

Molecular shape depends on the number of bonding pairs and lone pairs around a central atom. These pages separate the key geometries so that students can revise electron-pair repulsion, bond angles and how lone pairs change the final shape.

Exam Papers
Paper 1 & 2
9CH0/01 and 9CH0/02
Specification Points
2.10 – 2.12
3 points covered
Sub-topics
11 lessons
Revision notes available
Exam Board
Edexcel
Pearson 9CH0

Revision Notes

Work through each part of Edexcel Topic 2 in a structured sequence.

Shapes of Molecules
Linear
two bonding pairs, 180°
1

Linear

Revise linear molecules with two bonding regions around the central atom and a bond angle of 180°.

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Shapes of Molecules
Trigonal Planar
three bonding pairs, 120°
2

Trigonal Planar

Learn trigonal planar geometry, where three bonding regions arrange at 120° around the central atom.

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Shapes of Molecules
Tetrahedral
four bonding pairs, 109.5°
3

Tetrahedral

Revise tetrahedral molecules with four bonding pairs and bond angles of about 109.5°.

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Shapes of Molecules
Trigonal Pyramidal
three bonding pairs, one lone pair, 107°
4

Trigonal Pyramidal

Understand how one lone pair changes a tetrahedral electron-pair arrangement into a trigonal pyramidal shape.

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Shapes of Molecules
Bent
two bonding pairs, two lone pairs, 104.5°
5

Bent

Learn how lone pairs compress bond angles and produce bent or V-shaped molecules such as H₂O.

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Shapes of Molecules
Trigonal Bipyramidal
five bonding pairs, 120° and 90°
6

Trigonal Bipyramidal

Revise five-region electron-pair geometry with axial and equatorial positions.

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Shapes of Molecules
Octahedral
six bonding pairs, 90°
7

Octahedral

Learn octahedral geometry, where six bonding regions arrange at 90° around the central atom.

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Shapes of Molecules
Square Planar
four bonding pairs, two lone pairs, 90°
8

Square Planar

Revise square planar shapes formed from octahedral electron-pair arrangements with two opposite lone pairs.

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Shapes of Molecules
Square Pyramidal
five bonding pairs, one lone pair
9

Square Pyramidal

Understand square pyramidal molecules and how one lone pair affects an octahedral arrangement.

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Shapes of Molecules
Distorted T
three bonding pairs, two lone pairs
10

Distorted T

Learn distorted T-shaped molecules where lone pairs alter the arrangement of bonding pairs around the central atom.

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Shapes of Molecules
SeeSaw
four bonding pairs, one lone pair
11

SeeSaw

Revise seesaw shapes formed from trigonal bipyramidal electron-pair arrangements with one lone pair.

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Summary map

Download, print and revise the key facts of this topic at a glance.

Summary map · PDF

Shapes of Molecules Map

Edexcel A Level Chemistry · Topic 2 Bonding and Structure · Shapes of Molecules

The whole section on one A4 page: electron-pair repulsion, every shape from two to six pairs, lone pairs, related species and polar molecules.

Download the map6 key ideas + a table of shapes · A4 portrait · print ready

© 2026 Online Learning System. For personal study: printing is allowed; editing, copying and redistribution are not.

Virtual Lessons

Virtual Lessons
Watch
& learn
2 video lessons
With the course

Virtual Lessons

Taught step by step in 2 recorded video lessons, to watch at your own pace.

See what is inside

Topic 2A Shapes of Molecules taught by a specialist chemistry teacher, in 2 recorded video lessons that follow the specification.

  • Learn it before you revise itEach lesson explains the chemistry step by step, with the diagrams, mechanisms and worked examples the exam expects.
  • At your own pacePause, rewind and rewatch any part. Each lesson opens where you stopped.
  • Your progress is keptA lesson is ticked off once you have watched most of it, here and in your course on Moodle.
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Multiple Choice Question Exam Practice

Multiple choice
Test
yourself
MCQ (A) to (B)
MCQ (A) free

Test yourself: 2 MCQ papers

Exam-style multiple-choice papers, marked the moment you submit with every answer explained. MCQ (A) is free.

Start MCQ (A) free

2 exam-style multiple-choice papers, MCQ (A) to (B): 42 questions on Topic 2A Shapes of Molecules, written the way the exam asks them.

  • Marked the moment you submitYour score straight away, with every answer explained, right or wrong.
  • Revise what you missedEach explanation links to the revision notes for that point.
  • MCQ (A) is freeTry the first paper now. MCQ (B) comes with the course.
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Exam Practice Questions

Teacher marked
Write
& draw
3 exam papers
With the course

Written and drawn answers: 3 papers

Draw, write and calculate the way the exam asks, then a specialist chemistry teacher marks your work.

See what is inside

3 exam papers, (A) to (C): 34 questions on Topic 2A Shapes of Molecules with no multiple choice. You write explanations, work out calculations and draw answers: structures, mechanisms and diagrams.

  • Answer the way the exam asksThe real paper wants written, worked and drawn answers, so that is how you practise.
  • Marked by a teacher, assisted by KASPA specialist chemistry teacher marks every answer against the mark scheme, with feedback on what to fix.
  • One paper marked each weekYour marked paper comes back here with every marking point shown.
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Specification

Specification Coverage

Shapes of Molecules – Edexcel A Level Chemistry

The following specification points outline the knowledge and skills students are expected to demonstrate for Topic 2.

2A: Bonding

2.10
understand that the shape of a simple molecule or ion is determined by the repulsion between the electron pairs that surround a central atom
2.11
understand reasons for the shapes of, and bond angles in, simple molecules and ions with up to six outer pairs of electrons, any combination of bonding pairs and lone pairs. Examples should include BeCl2, BCl3, CH4, NH3, NH4+, H2O, CO2, PCl5(g) and SF6(g) and related molecules and ions; as well as simple organic molecules in this specification.
2.12
be able to predict the shapes of, and bond angles in, simple molecules and ions analogous to those specified above using electron-pair repulsion theory
Specification Coverage

Shapes of Molecules – Edexcel A Level Chemistry

The following specification points outline the knowledge and skills students are expected to demonstrate for Topic 2.

2A: Bonding

2.10
understand that the shape of a simple molecule or ion is determined by the repulsion between the electron pairs that surround a central atom
2.11
understand reasons for the shapes of, and bond angles in, simple molecules and ions with up to six outer pairs of electrons, any combination of bonding pairs and lone pairs. Examples should include BeCl2, BCl3, CH4, NH3, NH4+, H2O, CO2, PCl5(g) and SF6(g) and related molecules and ions; as well as simple organic molecules in this specification.
2.12
be able to predict the shapes of, and bond angles in, simple molecules and ions analogous to those specified above using electron-pair repulsion theory