OCR A Jun 2012 Paper 1 Q3

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3 Magnesium and strontium are typical Group 2 metals. (a) Complete the electron configuration of a magnesium atom. 1s2[1] (b) The second ionisation energy of magnesium is 1064 kJ mol1. (i) Write an equation to represent the second ionisation energy of magnesium. Include state symbols.[2] (ii) Magnesium has a greater second ionisation energy than strontium. Explain why. In your answer, you should use appropriate technical terms spelled correctly.[3]OCR 2012<br />
 (c) A student watches a demonstration in which strontium is added to water. The equation for the reaction is shown below. Sr(s) + 2H2O(l) Sr(OH)2(aq) + H2(g) (i) Write the formulae of the aqueous ions formed when this reaction takes place.[2] (ii) In terms of electron transfer, explain why strontium has been oxidised.[1] (iii) Suggest two compounds which could be reacted together to produce Sr(OH)2.[1] (d) Sr(OH)2 can react with an acid to form SrSO3. (i) The systematic name for SrSO3 is strontium sulfate(IV). Why does the number (IV) have to be used here rather than simply naming this compound as strontium sulfate?[1] (ii) Suggest the formula of the acid used to form SrSO3.[1] [Total: 12]OCR 2012 Turn over<br />

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