OCR A AS Jun 2016 Paper 1 Q21

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12 SECTION B Answer all the questions. 21 A twenty pence coin contains copper and nickel. (a) Copper and nickel each exist as a mixture of isotopes. State the similarities and differences between the atomic structure of isotopes of the same element. SimilaritiesDifferences[2] (b) The copper used to make a batch of coins is analysed by mass spectrometry. The mass spectrum is shown below. relative abundance (%) 69.17% 30.83% 60 61 62 63 65 66 67 68 64 m / z (i) Calculate the relative atomic mass of the copper used to make the coins. Give your answer to two decimal places. relative atomic mass =[2]OCR 2016<br /> 13 (ii) One coin has a mass of 5.00 g and contains 84.0% of copper, by mass. Calculate the number of copper atoms in one coin. Give your answer in standard form and to three significant figures. number of copper atoms =[2] (c) Nickel(II) nitrate, Ni(NO3)2, can be prepared by reacting nickel(II) oxide with dilute nitric acid. (i) Write the equation for this reaction.[1] (ii) Ni(NO3)2 contains the NO3ion. The nitrogen atom bonds to the oxygen atoms with a single covalent bond, a double covalent bond and a dative covalent bond, as shown below. O Draw the dot-and-cross diagram for the NO3 Use a different symbol for the extra electron.ion, showing outer shell electrons only. [2]OCR 2016 Turn over<br />

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