Some metals are very unreactive and exist in the Earth's crust as native, uncombined elements. More reactive metals are found combined with other elements in rocks known as ores.
Which of these metals is found as an uncombined element in the Earth's crust?
Calcium
Iron
Platinum
Sodium
110 exam-style questions on Edexcel GCSE Chemistry 5.1 Obtaining and using metals, covering 5.1.1 The reactivity series of metals, 5.1.2 Displacement reactions as redox reactions, 5.1.3 Extracting metals from ores by reduction, 5.1.4 Biological methods of metal extraction, 5.1.5 Resistance to oxidation and recycling metals, and 5.1.6 Life cycle assessment. Each one has a worked solution and a mark scheme showing where the marks go.