Atomic StructureTopic Summary
Topic Summary: Development of the Periodic Table
Part of Development of Periodic Table — GCSE Chemistry
This topic summary covers Topic Summary: Development of the Periodic Table within Development of Periodic Table for GCSE Chemistry. Revise Development of Periodic Table in Atomic Structure for GCSE Chemistry with 20 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 13 of 13 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 13 of 13
Practice
20 questions
Recall
20 flashcards
Topic Summary: Development of the Periodic Table
Key Scientists
- Döbereiner (1817): Triads — groups of 3 by mass
- Newlands (1866): Octaves — every 8th element similar
- Mendeleev (1869): Gaps, predictions, swaps
- Moseley (1913): Ordered by atomic number
Must-Know Facts
- Early tables: ordered by atomic mass (wrong basis)
- Mendeleev left gaps for undiscovered elements
- Mendeleev predicted properties of missing elements
- Predictions confirmed by discovering gallium, germanium, scandium
- Modern table: ordered by atomic number (protons)
- Noble gases added in 1890s as Group 0