Shapes of Molecules
Use this landing page to move quickly between the main shapes of molecules revision pages for Cambridge Topic 3. Each card links to a focused page covering molecular geometry, bonding pairs, lone pairs, bond angles and VSEPR-based shape prediction.
Choose a Shapes of Molecules Page
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.
Key idea: Electron pairs repel each other and arrange themselves as far apart as possible. Lone pairs repel more strongly than bonding pairs, so they reduce bond angles and can change the observed molecular shape.
Linear
Revise linear molecules with two bonding regions around the central atom and a bond angle of 180°.
Start revisingTrigonal Planar
Learn trigonal planar geometry, where three bonding regions arrange at 120° around the central atom.
Start revisingTetrahedral
Revise tetrahedral molecules with four bonding pairs and bond angles of about 109.5°.
Start revisingTrigonal Pyramidal
Understand how one lone pair changes a tetrahedral electron-pair arrangement into a trigonal pyramidal shape.
Start revisingBent
Learn how lone pairs compress bond angles and produce bent or V-shaped molecules such as H₂O.
Start revisingTrigonal Bipyramidal
Revise five-region electron-pair geometry with axial and equatorial positions.
Start revisingOctahedral
Learn octahedral geometry, where six bonding regions arrange at 90° around the central atom.
Start revisingSquare Planar
Revise square planar shapes formed from octahedral electron-pair arrangements with two opposite lone pairs.
Start revisingSquare Pyramidal
Understand square pyramidal molecules and how one lone pair affects an octahedral arrangement.
Start revisingDistorted T
Learn distorted T-shaped molecules where lone pairs alter the arrangement of bonding pairs around the central atom.
Start revisingSeeSaw
Revise seesaw shapes formed from trigonal bipyramidal electron-pair arrangements with one lone pair.
Start revisingHow to Use These Pages
Start with the simpler two-, three- and four-region shapes before moving to structures with lone pairs. Then use the higher-coordinate examples to compare trigonal bipyramidal and octahedral electron-pair arrangements.
Exam focus: State the number of bonding pairs and lone pairs first, then give the shape and bond angle. When lone pairs are present, explain that lone pair–bond pair repulsion is stronger than bond pair–bond pair repulsion.
Copyright notice: This revision page, including its written explanations, layout and teaching sequence, is produced for Online Learning System by Dr. Mohammed Al-Fatah. It is intended for student revision and may not be copied, redistributed or republished without permission.
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