A LevelChemistryCambridge (CIE)Revision Notes13. An Introduction to AS Level Organic ChemistryShapes of Organic Molecules; σ & π BondsShapes of Organic Molecules; σ & π Bonds

Shapes of Organic Molecules; σ & π Bonds (Cambridge (CIE) A Level Chemistry): Revision Note

Exam code: 9701

Philippa Platt

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Straight, Branched & Cyclic Molecules

  • Straight, branched and cyclic organic molecules are also called aliphatic compounds as long as they do not contain a benzene ring

Straight-chain

  • Straight-chain organic molecules are those in which the carbon atoms are connected to each other in one continuous chain

 A straight-chain organic molecule

Structural formula of butane, showing a linear chain of four carbon atoms single-bonded with ten hydrogen atoms in total.
Pentane is a straight-chain organic molecule as the carbon atoms are connected in a straight line

Branched

  • Branched organic molecules have side groups attached to the main chain of carbon atoms

A branched organic molecule

Structural formula of 2,3-dimethylbutane, showing six carbon atoms bonded with hydrogen atoms in a branched configuration.
2-methylbutane is a branched organic molecule as the main chain (consisting of 4 carbon atoms) has a methyl branch

Cyclic

  • Cyclic organic molecules are those in which the carbon atoms are connected to each other in a ring shape

A cyclic organic molecule

Chemical structure diagram of cyclohexane, featuring a hexagonal ring of carbon atoms, each bonded to two hydrogen atoms.
Cyclopentane is a cyclic organic molecule as the carbons are attached to each other in a ring structure

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    Philippa Platt

    Author: Philippa Platt

    Expertise: Chemistry Content Creator

    Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener