This key facts covers The Key Groups You Must Know within The Periodic Table for GCSE Chemistry. Revise The Periodic Table in Atomic Structure for GCSE Chemistry with 20 exam-style questions and 24 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 5 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 5 of 12
Practice
20 questions
Recall
24 flashcards
🧪 The Key Groups You Must Know
Group 1 — The Alkali Metals (Li, Na, K, Rb, Cs, Fr)
- 1 electron in outer shell — easily lost to form +1 ions
- Very reactive metals (reactivity INCREASES down the group)
- React vigorously with water to produce hydrogen gas
- Soft, low density, low melting points for metals
Group 7 — The Halogens (F, Cl, Br, I, At)
- 7 electrons in outer shell — easily gain 1 to form -1 ions
- Very reactive non-metals (reactivity DECREASES down the group)
- Exist as diatomic molecules (F₂, Cl₂, Br₂, I₂)
- Form salts when reacting with metals (halogen means "salt-former")
Group 0 — The Noble Gases (He, Ne, Ar, Kr, Xe, Rn)
- Full outer shell — extremely stable, no need to react
- Very unreactive (also called inert gases)
- Exist as single atoms (monatomic)
- Used where unreactive gases are needed (light bulbs, balloons)