OCR A Jun 2016 Paper 1 Q3

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The elements of Period 2 and Period 3 of the Periodic Table are shown in Table 3.1. Group Period 2 Period 3 Li Na Be Mg Al Si Cl Ne Ar Table 3.1 (a) The elements in these two periods show a repeating pattern in chemical and physical properties. What is the name given to this repeating pattern of properties?[1] (b) State the element in Table 3.1 with: the lowest first ionisation energythe lowest fourth ionisation energythe lowest boiling point[3] (c) Gallium, atomic number 31, is in Period 4 of the Periodic Table. Gallium is a Group 3 element. Predict the formula of a gallium ion.[1]OCR 2016<br />
 (d) The melting points of the Period 3 metals sodium and magnesium are shown below. Metal sodium magnesium Melting point / C 98 649 Explain the differences in the melting points of sodium and magnesium, using the model of metallic bonding. In your answer you should use appropriate technical terms spelled correctly.[3] (e) When magnesium nitrate, Mg(NO3)2, is heated, it decomposes as shown. 2Mg(NO3)2(s) 2MgO(s) + 4NO2(g) + O2(g) A student heats 2.966 g of Mg(NO3)2, which decomposes as above. Calculate the total volume of gas formed, in cm3, at room temperature and pressure, RTP. total volume of gas formed =cm3 [3]OCR 2016 Turn over<br />
 (f) Fluorine forms several compounds with sulfur and with oxygen. (i) Give the formula and the name of the compound formed between fluorine and sulfur which has octahedral molecules. FormulaName[1] (ii) Fluorine reacts with aqueous sodium hydroxide to form the oxide F2O. Two other products are also formed. One product is an ionic compound with a relative formula mass of 42.0. Construct a balanced equation for this reaction.[2] (g) (i) Fluorine is the most electronegative element. Indicate any dipoles on the molecule of F2O below using partial charges. (ii) Suggest the shape of the F2O molecule and the FOF bond angle. ShapeBond angle(iii) What is the oxidation number of oxygen in F2O? Include the sign in your answer. [1] [1][1] [Total: 17]OCR 2016<br />
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