Which of these metals is found uncombined as a native element in the Earth's crust?
potassium
calcium
platinum
iron
Practise Edexcel GCSE Chemistry Obtaining and using metals with exam-style questions for Foundation and Higher tier. 110 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.