Canonical lesson CHEMISTRY20-U1-L23 · outcome 20-A2.10k · depth CURRICULUM_BASELINE

Unit A: Diversity of Matter and Chemical Bonding - outcome 20-A2.10k

• Course: CHEMISTRY20 (SCN2796)
• Lesson ID: CHEMISTRY20-U1-L23
• Official outcome: 20-A2.10k (KNOWLEDGE)
• Object type: canonical lesson (not a bootcamp session)
• Source: Alberta Chemistry 20 Program of Studies (2007, updated 2014)

Official outcome text

describe bonding as a continuum ranging from complete electron transfer to equal sharing of electrons

Learning intention

Meet 20-A2.10k with instruction, practice, and a check. The 10-session bootcamp does not replace this lesson.

Success criteria

1. Restate the outcome in classroom language without swapping in a different unit’s template.
2. Complete the worked-style task for this outcome.
3. Name the lab setting (classroom-supervised / teacher demo / dataset or simulation / forbidden).

Teaching

Bonding is a continuum: complete transfer (ionic) ↔ unequal sharing (polar covalent) ↔ equal sharing (nonpolar covalent). ΔEN is a guide, not a hard wall. Na-Cl is toward transfer; H-Cl polar covalent; Cl-Cl equal sharing. There is no separate “third type” that is neither ionic nor covalent for Chem 20 binary cases.

Worked example

Place NaCl, HCl, and Cl2 on the continuum and justify with ΔEN and whether a lattice of ions vs discrete molecules forms.

Guided practice

1. Place CsF, HBr, and F2 on the transfer-to-equal-sharing continuum with ΔEN justification. Do not copy NaCl/HCl/Cl2 unchanged.
2. Near-miss: “all compounds are either 100% ionic or 100% covalent.” Mark the first wrong line.

Independent practice

1. Where does SiCl4 sit relative to NaCl and Cl2?
2. Two sentences: lattice of ions vs discrete molecules.
3. ΔEN large vs small - expected bond type.

Diagram / whiteboard

Approved diagram id chem20-ionic-lattice - Ionic lattice / bonding sketch. Tutor may open the course whiteboard and display this id. Do not invent hazardous procedures on the board.

Checks for understanding

Use the formative evidence below as the exit check for this outcome. Correct the misconception named in this lesson before praising.

Misconception to repair

Teaching a sharp cutoff “ΔEN > 1.7 is always ionic” with no continuum language.

Safety and lab register

Setting: classroom-supervised only for Session 04 conductivity (NaCl / sucrose / ~5% vinegar, 9 V LED or school probe). All other Unit A work is paper, models, data cards, or approved simulation. Forbidden: bleach+acid, bleach+ammonia, flames, tasting, home copy of Session 04, concentrated acids/bases, generating Cl2. AI Tutor must not invent labs outside CHEM20_LOW_RESOURCE_LAB_REGISTER.csv.

Alberta Poison Control if a real exposure is occurring: 1-844-764-7669. The AI Tutor is not a poison centre.

Formative evidence

Continuum sketch with NaCl, HCl, Cl2 labelled.

This is not a diploma. Mastery needs instruction + activity + check.

AI Tutor / human tutor

Ground on 20-A2.10k. No false praise. No invented procedures. No silent skip to a different unit. Human tutor if the student describes mixing bleach, tasting, or flames.

Provenance

Official POS wording from ALBERTA_SENIOR_HIGH_OFFICIAL_OUTCOMES.csv. Pack lesson written to replace Wave-4 contaminated canonical markdown.