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4.1.2.2 Development of the periodic table
Paper 1 · Higher combined
Spec reference: 4.1.2.2 (under 4.1.2).
What you need to know
- Development of the Periodic Table In the early 1800s, elements were arranged by atomic mass. The periodic table was not complete because some of the elements had not been found.…
- Metals and Non-metals They are found at the left part of the periodic table. Non-metals are at the right of the table. Metals Are strong, malleable, good conductors of electrici…
- Dimitri Mendeleev (1869) left gaps in the periodic table. He put them in order of atomic mass. The gaps show that he believed there was some undiscovered elements. He was right!…
Support videos
- FreeScienceLessons (topic playlist): (use links below)
- FreeScienceLessons (Atomic structure playlist): https://www.youtube.com/playlist?list=PL9IouNCPbCxULWXCO9jt0PsuAbxYpw2_1
Self-assessment (checklist)
- I can calculate the number of protons, neutrons and
Key steps (method)
- Identify what the question is testing and use precise chemistry vocabulary.
- If it’s a calculation: write the equation/formula first, then substitute carefully.
Common mistakes
- Missing units/state symbols when asked.
- Giving a statement without linking cause → effect.
Exam-style questions (quick)
- Define the key term(s) for this point in the spec.
- Explain a typical property/result using particle/bonding ideas.
- Do a short calculation or interpretation step relevant to this point.
Practice questions
- PMT: Atomic structure (questions + notes): https://www.physicsandmathstutor.com/chemistry-revision/gcse-aqa/atomic-structure-and-periodic-table