I've come across a question that is "Account for the existence of isotopes." and is only worth 2 marks. I'm unsure, but it is as simple as explaining that isotopes are atoms of the same element but with a different number of neutrons and so a different mass number, or do I need to go into the J.J Thomson experiement or something else? It's only 2 marks, so surely the latter isn't necessary.
The wording is my achilles heel yet again, as I'm thinking my answer would merely answer the question if it said define the term isotope. Oh dear, I don't know. Any input would be helpful here.
Also, there is this question for 14 marks:
"Isotopes can be seperated in a mass spectrometer. Show how this is possible by describing the various parts of a mass spectrometer and by discussing the principles of operation in each part."
I know my stuff, but would like to know how you would go about answering the question. Layout, etc.
Thanks very much.
The two mark question, I'll write the definition and give example by using chlorine.
Refer to here: http://answers.yahoo.com/question/index?qid=20070524060754AAPIbsM
For the 14 mark question, it tests you on your understanding of a mass spec.