A1 (a) Choose from the following elements to answer the questions. calcium chlorine chromium copper krypton nitrogen oxygen sodium sulfur Each element may be used once, more than once or not at all. Which element:

1. (a)(i)is a monatomic gas,[1]
2. (a)(ii)makes up 78% of dry air,[1]
3. (a)(iii)has an oxide which reacts with the impurities in a blast furnace to form slag,[1]
4. (a)(iv)forms aqueous ions with a 2+ charge which give a dark blue solution on addition of excess aqueous ammonia,[1]
5. (a)(v)reacts with propane in the presence of ultraviolet light by a substitution reaction?[1]
6. (b)Complete the table to show the number of electrons and number of neutrons in the sulfur atom and in the magnesium ion. number of electrons number of neutrons 33 S 16 25 12Mg2+[4]