plumiOCR A‑Level Chemistry B questions by topic
Every question from every OCR A-Level Chemistry B (Salters) paper, 2016–2025, part by part. Filter by topic, paper or year, open the mark scheme under any question, and download a set as a PDF.
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![June 2025 Paper 1, question 7: Which row shows the correct electron configurations of Cr and Cr3+? 7 Cr3+ Cr [Ar] 3d4 4s2 [Ar] 3d3 A [Ar] 3d4 4s2 [Ar] 3d1 4s2 B [Ar] 3d5 4s1 [Ar] 3d3 C [Ar] 3](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h43301-jun25-07-qp.webp?v=3)
![June 2025 Paper 1, question 19: 2.00 g of an oxide of copper contains 1.78 g of copper. What is the oxidation state of the copper in the oxide? A –1 B 0 C +1 D +2 Your answer [1]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h43301-jun25-19-qp.webp?v=3)
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