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(a) The diagram below represents part of the structure of a sodium chloride crystal. The position of one of the sodium ions in the crystal is shown as
#o+#
(i) On the diagram , mark the positions of the other three sodium ions.
(ii) The melting and boiling points of sodium chloride are #801^0C# and #1413^0C# respectively. Explain why sodium chloride does not conduct electricity at #25^0C#, but does so at temperatures between #801^0C# and #1413^0C#.
(b) Give a reason why ammonia gas is highly soluble in water.
(c) The structure of an ammonia ion is shown below:
Name the type of bond represented in the diagram by# NtoH#
(d) Carbon exists in different crystalline forms. Some of these forms were recently discovered in soot and are called fullerenes.
(i) What name is given to different crystalline forms of the same element?