Cambridge IGCSE·Co-ordinated Sciences 0654·Chemistry
The Periodic Table
Key knowledge — The Periodic Table
Key facts & rules
- Periods: rows — number of electron shells increases across a period. Group: columns — same number of outer electrons.
- Group 1 (alkali metals): react with water → metal hydroxide + hydrogen. Reactivity increases DOWN the group.
- Group 7 (halogens): diatomic molecules (F₂, Cl₂, Br₂, I₂). Reactivity DECREASES down group. More reactive halogen displaces less reactive one.
- Group 0 (noble gases): full outer shell → very unreactive, exist as single atoms.
- Transition metals: in the middle block. Variable oxidation states, form coloured compounds, good catalysts.
- Metallic character increases down a group and decreases across a period (left to right).
- Across period 3: Na, Mg, Al are metals; Si is metalloid; P, S, Cl, Ar are non-metals.
IGCSE Chemistry — The Periodic Table
1568 Cambridge IGCSE 0654 chemistry past paper questions on the periodic table, organised by subtopic. Pick a subtopic to start practising.
About the periodic table on IGCSE 0654
Group and period trends, Group I, Group VII and Group VIII, and the transition elements.