OCR A Jun 2009 Paper 1 Q4

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Ionisation energies have been used to develop the model of the atom. The first ionisation energies of the elements Li to Na are shown in the figure below. 1st ionisation energy / kJ mol1 2500 2000 1500 1000 500 2081 1681 1402 1314 1086 900 801 520 496 Li Be Ne Na (a) Define the term first ionisation energy.[3] (b) (i) Explain why the first ionisation energies show a general increase from Li to Ne.[3]OCR 2009<br />
 (ii) Explain the difference between the first ionisation energies of Li and Na. In your answer, you should use appropriate technical terms, spelt correctly.[3] (c) The first ionisation energy of oxygen is 1314 kJ mol1 and the second ionisation energy of oxygen is 3388 kJ mol1. (i) Write an equation to represent the second ionisation energy of oxygen. Include state symbols.[1] (ii) Suggest why the second ionisation energy of oxygen has a greater value than the first ionisation energy of oxygen.[1] [Total: 11]OCR 2009 Turn over<br />

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