The Key Groups You Must Know
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 22 exam-style questions and 24 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 5 of 13 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 13
Practice
22 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)
Keep building this topic
Read this section alongside the surrounding pages in The Periodic Table. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for The Periodic Table
How are elements arranged in the modern periodic table?
Mendeleev's periodic table was eventually accepted by other scientists. Explain why scientists were convinced that his table was correct.
Quick Recall Flashcards
22 questions on The Periodic Table — practise free
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