Why is potassium more reactive than sodium?
The metallic bonds in potassium are stronger than those in sodium.
Potassium is a softer metal than sodium.
The outer electron of a potassium atom is further from the nucleus than sodium's.
Potassium has a more exothermic reaction with water than sodium does.
75 exam-style questions on Edexcel GCSE Chemistry 7.1 Group 1, covering 7.1.1 Classifying elements by group in the periodic table and 7.1.2 Properties and reactions of the alkali metals. Each one has a worked solution and a mark scheme showing where the marks go.