James picks up a brittle black solid that he calls element Z. He notes that it can conduct heat and electricity and that it is often used to make fires for cooking or heating. It can
also be found in another form, a clear solid that is very hard. This form of Z is often
used in fine jewellery. It does not react with acids.
a) ls element Z a metal or a non-metal? Give a reason for your answer.
b) Identify element Z.
c) Explain why element Z can be found as a brittle black solid, and a colourless hard
solid if it is the same element.​