topic 11 + 12: Group 17 + Nitrogen and Sulfur

11.1.2 describe and explain the trend in the bond strength of the halogen molecules

11.2.2 describe the reactions of the elements with hydrogen and explain their relative reactivity in these reactions

11.2.3 describe the relative thermal stabilities of the hydrogen halides and explain these in terms of bond strengths

11.3.3 describe and explain the reactions of halide ions with: (a) aqueous silver ions followed by aqueous ammonia (the formation and formula of the [Ag(NH3) 2] + complex is not required) (b) concentrated sulfuric acid, to include balanced chemical equations

11.4.2 explain, including by use of an equation, the use of chlorine in water purification to include the production of the active species HOCl and ClO– which kill bacteria

12.1.1 explain the lack of reactivity of nitrogen, with reference to triple bond strength and lack of polarity

12.1.2 describe and explain: (a) the basicity of ammonia, using the Brønsted–Lowry theory (b) the structure of the ammonium ion and its formation by an acid–base reaction (c) the displacement of ammonia from ammonium salts by an acid–base reaction

12.1.3 state and explain the natural and man-made occurrences of oxides of nitrogen and their catalytic removal from the exhaust gases of internal combustion engines