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Chemistry

HS Chemistry · Unit 1 · Atomic Structure

Protons decide. Neutrons weigh. Electrons fill 2, 8, 8, 2.

Everything on the Unit 1 Major: particles, nuclear notation, Bohr models, core and valence electrons, isotopes and average atomic mass.

Major Assessment Fri 9 Oct · Unit 1 only
Ready for Unit 1Start with Lesson 1 — the meter fills as you answer.My progress →

What the Major will probably ask

From the review worksheet and its answer key, the Unit 1 revision sheet the teacher posted for the Major, and the review-session slides. A prediction, not the paper — the atoms will be different, so practise the method.

Composition from Z and A (or nuclear notation): protons, neutrons, electrons, elementVery likelyReview worksheet Q3–4, revision sheet Q2, every Do Now.Write nuclear notation (A on top, Z below) and the isotope nameVery likelyReview worksheet Q5, revision sheet Q3 and Q6.Draw a complete Bohr model (p and n in the nucleus, every electron), arrangement, core & valenceVery likelyReview worksheet Q6–7, revision sheet Q7 — Al-27 and Cl-35 keep coming back.Error analysis: "2, 7, 8 is correct because it adds to 17"Very likelyReview worksheet Q8, the sulfur and sodium slides.Isotopes from a table — and the trap: same mass number, different elementsVery likelyReview worksheet Q9, revision sheet Q5 and Q15.Average atomic mass: predict, calculate (with amu), check it's reasonableVery likelyReview worksheet Q11–12, revision sheet Q12–14.Evaluate a claim (synthesis): identity, isotopes, mass numbers, evidenceVery likelyReview worksheet Q13, review session synthesis, revision sheet Q15.A–D multiple choice, including fixing a Bohr modelLikelyThe revision sheet (posted for the Major) mixes MCQ with written parts.Particle discoveries and relative masses (Thomson, Rutherford, Chadwick; 1/1836)PossibleIn the L01.2 reading, but not on either review sheet.

Three days, spaced

Spreading it over three days and testing yourself each day beats one long night — the forgetting in between is what makes the next recall stick.

  1. TueLessons 1–4 (particles, notation, Bohr, valence) + 5 composition drills.
  2. WedLessons 5–7 (isotopes, average mass, evaluate) + Bohr and average-mass drills.
  3. ThuMock Major, timed. Then fix every miss — and redo the Minor paper's mistakes from its feedback.
  4. FriMorning: memory sheet in cover mode, 10 minutes. Bring your notebook — the notebook check is due too.

Learn

7 lessons: Do Now, a memory hook, an atom to play with, then the teacher's question formats.

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Atom lab

Build any of the first 20 atoms; compare isotopes; balance an average mass.

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Teacher's questions

The review worksheet, the Major revision sheet and the slide tasks — marked with worked steps.

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Drills

Endless fresh questions: composition, notation, Bohr, isotopes, average mass.

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Mock Major

A full unseen paper: MCQ, structured and explain-&-evaluate.

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Memory sheet

Hooks, rules, the first 20 arrangements and answer frames — with cover mode.

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Ready, lesson by lesson