CIE AS Chemistry (9701) exams from 2022

Revision Notes

3.1.9 Planarity of Organic Molecules

Planar Molecules

  • Planar molecules have all their atoms in the same plane
    • Eg. linear, bent, trigonal planar and square planar

 

An Introduction to AS Level Organic Chemistry Planar Molecules, downloadable AS & A Level Chemistry revision notes

Molecules which have all their atoms in the same plane

  • The presence of an sp2 hybridised carbon can force the molecule to adopt a planar configuration (trigonal planar)
  • The 3 σ bonds position themselves in a trigonal planar position so that the bonding pair of electrons are as far away from each other and therefore minimise the repulsion between them
    • Eg. ethene

 

An Introduction to AS Level Organic Chemistry Planar Ethene, downloadable AS & A Level Chemistry revision notes

Ethene is a planar molecule with two trigonal planar centres around the carbon atoms

  • Eg. propene

 

An Introduction to AS Level Organic Chemistry Planar Propene, downloadable AS & A Level Chemistry revision notes

Propene has two trigonal planar centres around the carbon-carbon double bond and one tetrahedral centre

  • The presence of an sp hybridised carbon can also force the molecule to adopt a planar configuration (linear)
  • The 2 σ bonds position themselves in a linear position to minimise the repulsion between the bonding pairs of electrons
    • For example, ethyne

 

An Introduction to AS Level Organic Chemistry Planar Ethyne, downloadable AS & A Level Chemistry revision notes

Ethyne is a planar molecule with one planar centre: the molecule is linear

  • Eg. propyne

 

An Introduction to AS Level Organic Chemistry Planar Propyne, downloadable AS & A Level Chemistry revision notes

Propyne has one planar centre around the carbon-carbon triple bond (linear) and one tetrahedral centre

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.
Close

Join Save My Exams

Download all our Revision Notes as PDFs

Try a Free Sample of our revision notes as a printable PDF.

Join Now
Already a member?
Go to Top