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Chemguide Support for Edexcel IGCSE Chemistry |
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Extra material needed for the 2010 exam - Chapter 3 This page lists the material from the old Edexcel syllabus which isn't covered by my new Edexcel IGCSE Chemistry book. Shapes of molecules As well as a knowledge of the bonding, the old syllabus also asked for the shapes of carbon dioxide and methane molecules. Carbon dioxide The molecule is linear - in other words, all the atoms are arranged in a straight line consisting of an oxygen atom, a carbon atom and then the second oxygen atom. Methane Methane is described as a tetrahedral molecule. A tetrahedron is a regular pyramid with a triangular base. You can think of the carbon atom sitting in the centre of the tetrahedron, and hydrogen atoms at each of the four corners. You will find a simple diagram of a model of methane at the top of page 256. Return to complete list of extras © Jim Clark 2009 |