OCR A Jan 2010 Paper 1 Q1

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Answer all the questions. Europium, atomic number 63, is used in some television screens to highlight colours. A chemist analysed a sample of europium using mass spectrometry. The results are shown in Table 1.1 below. isotope 151Eu 153Eu relative isotopic mass abundance (%) 151.0 153.0 Table 1.1 47.77 52.23 (a) Define the term relative isotopic mass.[2] (b) Using Table 1.1, calculate the relative atomic mass of the europium sample. Give your answer to two decimal places. answer =[2]OCR 2010<br /> (c) Isotopes of europium have differences and similarities. (i) In terms of protons, neutrons and electrons, how is an atom of 151Eu different from an atom of 153Eu?[1] (ii) In terms of protons, neutrons and electrons, how is an atom of 151Eu similar to an atom of 153Eu?[1] (d) Modern plasma television screens emit light when mixtures of noble gases, such as neon and xenon, are ionised. The first ionisation energies of neon and xenon are shown in the table below. element neon xenon 1st ionisation energy / kJ mol1 +2081 +1170 Explain why xenon has a lower first ionisation energy than neon.[3]OCR 2010 [Total: 9] Turn over<br />

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