This exam focus covers Worked Model Answer within Group 1: Alkali Metals for GCSE Chemistry. Revise Group 1: Alkali Metals in Atomic Structure for GCSE Chemistry with 22 exam-style questions and 20 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 12 of 13 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
📝 Worked Model Answer
Question: "Explain why Group 1 metals become more reactive going down the group." (4 marks)
Going down Group 1, each element has more electron shells. [1] This means the outer electron is further from the nucleus. [1] There is also greater electron shielding from the inner shells, which reduces the attraction between the nucleus and the outer electron. The overall electrostatic attraction holding the outer electron is therefore weaker. [1] This makes it easier for the atom to lose its outer electron in reactions, so the element is more reactive. [1]
Examiner note: Full marks require four separate, linked ideas: more shells, greater distance, weaker attraction, easier to lose electron. Simply writing "the outer electron is easier to lose" without the structural reason earns only 1 mark. Mentioning shielding is not required but strengthens the explanation at higher grades.
Practice questions for Group 1: Alkali Metals
How many electrons do alkali metals have in their outermost shell?
Explain why potassium is more reactive than sodium when it reacts with water.