GCSE Chemistry: The Periodic Table

The periodic table is chemistry's master document, and GCSE questions about it test two things: whether you know the story of how it was built, and whether you can use group patterns to predict behaviour. This quiz covers both.

The historical questions centre on Mendeleev's crucial insight — leaving gaps for undiscovered elements and predicting their properties, the move that turned a cataloguing exercise into a predictive science — and the modern table's arrangement by atomic number with elements of similar properties falling into the same groups.

The group chemistry forms the heart of the set. Group 1 gets the full treatment: the observable events when sodium meets water (floating, fizzing, the alkaline solution left behind) and the explanation for increasing reactivity down the group in terms of the outer electron becoming easier to lose. Group 7 mirrors it from the opposite direction: chlorine displacing bromine from potassium bromide solution, and reactivity decreasing down the group because attracting an extra electron gets harder. Group 0's inertness is tied to full outer shells, and the physical trend of increasing boiling point down the noble gases gets its own question.

The metals/non-metals divide is tested through characteristic properties — positive versus negative ion formation, conductivity, melting points — in multi-select questions that force you to evaluate each property claim individually rather than pattern-match.

Every question is self-contained, every explanation names the principle at work, and the distractors encode the classic reversals: reactivity trends flipped between Groups 1 and 7, and Mendeleev credited with ordering by atomic number. Together with the Atomic Structure quiz, this set covers the first major strand of the GCSE chemistry specification.

• Explain how Mendeleev's gaps and predictions shaped the periodic table
• Describe the modern table's arrangement by atomic number and groups
• Predict and explain reactions and reactivity trends of Group 1 alkali metals
• Predict displacement reactions and the reactivity trend of Group 7 halogens
• Account for the inertness of Group 0 and distinguish metal from non-metal properties

Topic scope follows the Department for Education's GCSE combined science subject content, atomic structure and the periodic table strand: the development of the periodic table, group properties of alkali metals, halogens and noble gases, and reactivity trends explained by electronic structure.