OCR A-Level Chemistry Revision
Explore OCR A-Level Chemistry revision topics. Check the official specification for complete requirements for your exam year and route.
Qualification code: H432
Course details
Assessment For assessment details, see the official specification.
Tick a point after revising it. Progress is saved on this device and does not measure mastery.
Reviewed course guidance
Revision points, with the explanation beside them
Open a point to read what to know, how to use it in an assessment, a plain-language explanation and a self-check. Answers stay hidden until you choose to reveal them.
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Topic group
Reviewed requirements
- Core
Open revision guidance
What to know
- Atomic number Z is the proton count. Mass number A is protons plus neutrons, so neutrons = A−Z. In a neutral atom electrons equal protons; a positive charge means electrons have been removed and a negative charge means they have been gained.
What to do in an assessment
- Use the charge magnitude to adjust electron count, not proton count. Check that the resulting charge agrees with protons minus electrons.
In plain language
The nucleus determines proton and neutron counts; forming an ion only changes electrons.
Self-check
For ³⁵Cl⁻, Z = 17. How many protons, neutrons and electrons?
Show the answer
Protons = 17; neutrons = 35−17 = 18; electrons = 17+1 = 18.
Earlier topic checklist
These earlier topic ticks are separate from the reviewed points above and do not count towards that progress.
Chemistry topic list
This is a topic overview, not a complete specification checklist. Check the official course for all assessed content, options and your exam year.
These headings appear to follow Chemistry A (H432), not Chemistry B. Confirm which specification your school uses.
Tick each item off as you revise. Ticks are saved on this device only.
These ticks keep your earlier topic checklist. They do not count towards the new reviewed requirements above. Its numbering may be internal; use the linked references above for the exact reviewed source requirements.
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How OmniStudy helps you revise
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