OCR A Jan 2013 Paper 1 Q2

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2 Simple molecules are covalently bonded. (a) State what is meant by the term covalent bond.[1] (b) Chemists are able to predict the shape of a simple covalent molecule from the number of electron pairs surrounding the central atom. (i) Explain how this enables chemists to predict the shape.[2] (ii) The dot-and-cross diagram of the simple covalent molecule, H3BO3, is shown below. xO xO B O H Predict the OBO and BOH bond angles in a molecule of H3BO3. OBO =BOH =[2] (c) Give an example of a simple covalent molecule which has all bond angles equal to 90.[1] [Total: 6]OCR 2013<br />

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