This definitions covers Key Definitions 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 7 of 13 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
📖 Key Definitions
Alkali metals: The elements in Group 1 of the periodic table (Li, Na, K, Rb, Cs, Fr) — reactive metals with 1 outer electron that form +1 ions and alkaline hydroxides when they react with water.
Reactivity trend (Group 1): Reactivity increases going down Group 1 because the outer electron is further from the nucleus and more shielded, making it easier to lose.
Electron shielding: The reduction in nuclear attraction experienced by outer electrons due to the repulsion from inner electron shells.
Metal hydroxide: The alkaline product formed when an alkali metal reacts with water, e.g., sodium hydroxide (NaOH), potassium hydroxide (KOH).
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.