Count electron regions around the central atom, arrange them for minimum repulsion and reduce angles where lone pairs exert stronger repulsion than bonding pairs.
The elements carbon and silicon both form dioxides.
The shape of the carbon dioxide molecule affects its physical properties.
Explain the shape of the carbon dioxide molecule.
An explanation that makes reference to the following points: - there are two sets of bonding electrons (and no lone pairs) about the carbon atom - which arrange to minimise repulsion (1) - resulting in a linear shape / bond angle of 180^ (1) Any indication of two regions of electrons (this includes a correct diagram) e.g. O=C=O Allow two double bonds Allow maximum separation / to be as far apart as possible Accept bond angle labelled on a diagram Ignore references to symmetry Ignore references to lone pairs on oxygen All marks are independent No TE for any mark