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Year 11 / Chemistry / Term 1 / Weeks 01 02 / Teacher

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Public teacher-facing worked key and next movesYear 11 Chemistry · T1 W1–2 · Teacher · Answer And Next

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Teacher copy · prompts and answer keys

Teacher copy: This page may include teaching prompts or answer keys. Answer keys in this public library can be viewed by anyone. Give learners a clean prompt, use checks as formative evidence, and change a case locally when prior access matters.

This answer page is public by URL. Days 5/10 are useful first-encounter formative prompts only when learners have not previewed it; use locally authored parallel files if previous access matters. Record original work and the support used. A correct dictated/AAC calculation can show the Chemistry target even when reading was supported; it does not establish independent reading. A supplied chemistry step or answer makes the response supported. None of these responses is a QCAA Unit 1 grade or school assessment instrument.

Day Worked target answer If the learner gets stuck, next teaching move
1 Nucleus contains positive protons and neutral neutrons; negative electrons are modelled outside at distinct energy levels. The rings are not measured circular paths. Point to Card A's “model” label; ask learner to separate a drawn convention from an observation.
2 C Z6→6 protons; O Z8→8; Mg Z12→12. Story labels such as “fibre” do not identify an element without given chemical evidence. Z alone does not give neutron count. Cover symbols and match given Z to the symbol table, then uncover and explain.
3 Neutral C-12: p6 n6; O-16: p8 n8; Mg-24: p12 n12. Check 6+6=12, 8+8=16, 12+12=24. A is an integer nucleon count for one isotope; periodic atomic weight can be a decimal average. Use the count mat's A = p+n line, then physically move Z p-tokens away from A total tokens.
4 C-12/C-13: same Z6, n6/n7. Cl-35/Cl-37: same Z17, n18/n20. Both pairs are different isotopes of their respective element. The cards give no natural abundance. Ask which number must stay equal for “same element”; calculate n with A−Z twice.
5 See full File R/S work below. Revisit only the failed count or inference, then give a different local pair.
6 ^{26}_{12}Mg: magnesium-26, A26 Z12 neutral by task convention; p12 n14 e12. ^{23}_{11}Na: sodium-23, A23 Z11 neutral; p11 n12 e11. A is upper left, Z lower left. Read “name, A, Z, charge” aloud, then calculate each count without using the decimal periodic weight.
7 Neutral Na-23 p11 n12 e11 → Na-23 1+ p11 n12 e10. Neutral Mg-24 p12 n12 e12 → Mg-24 2+ p12 n12 e10. Positive charge follows electron loss from same nuclide; nuclei stay fixed. Keep proton/neutron tokens glued to the paper card and remove only electron counters.
8 Neutral Cl-35 p17 n18 e17 → Cl-35 1− p17 n18 e18. Neutral O-16 p8 n8 e8 → O-16 2− p8 n8 e10. A/Z remain fixed. Charge checks 17−18=−1 and 8−10=−2. Add electron counters without moving p/n; have learner verify with p−e.
9 Plus charge in the same nuclide model means fewer electrons, not more protons; C-12/C-13 share Z6 so are same element/different isotopes; 23 in Na-23 is A, while Na has Z11; fictional catalogue label does not prove purity/composition. Ask learner to point to the exact given symbol/status, then name the rule and unsupported leap.
10 See full File T/U work below. Target the first count rule that broke, then use a different locally unseen charged card.

Day 5 Check A · worked File R/S key

File Z A protons p neutrons n = A−Z neutral electrons e reverse check
R · boron-10 5 10 5 10−5=5 5 5+5=10
S · boron-11 5 11 5 11−5=6 5 5+6=11

They are two isotopes of boron: both have Z5/five protons, while neutron count and A differ. They are not different elements and not the same isotope. A full-word reading of R is “boron-10, mass number 10, atomic number 5, neutral atom”; S substitutes 11. Neither fictional file reports actual ceramic content, relative abundance, dose, suitability or safety. Next move: if p/e are confused, compare the explicit “neutral” word with e=Z; if n was added, reverse-check p+n; if isotope classification fails, line up the two Z cards before looking at A. Preserve first response and give an unseen local pair for recheck.

Day 10 Check B · worked File T/U key

File Z A protons p neutrons n = A−Z ion electrons e charge check same-isotope neutral e
T · calcium-40 2+ 20 40 20 40−20=20 20−2=18 20−18=+2 20
U · fluorine-19 1− 9 19 9 19−9=10 9+1=10 9−10=−1 9

In each neutral-to-ion comparison, electron number changes while p, n, Z, A, element and isotope remain fixed. T and U are not isotopes of each other: Z20 versus Z9 means different elements. The cards cannot prove that a real transit sign/conserved item contains those ions, that an isolated ion is stable in a particular environment, how a reaction occurred or whether a material is safe. Next move: if a student changes proton count to account for charge, keep the nucleus strip in place and change only electron counters; if they call T/U isotopes, compare Z before A; if they infer product composition, return to the word “fictional.” Recheck with a newly written local card.

Arithmetic audit: every p, n and e entry above follows p=Z, n=A−Z, e=Z if neutral, and p−e=q for monoatomic charge q in elementary-charge units. The local verifier independently recomputes the check triples and selected practice triples from structured constants; the above tables must agree. Chemical status is given by each paper card, not produced in a lab.

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