This packet is everything a parent or guide needs to assess Unit 02 at home — learning targets, the answers that count as correct, the mastery rubric, calibration examples, and a clipboard score sheet. No multiple-choice test: the student shows mastery by building accurate molecular models and predicting properties from structure.
By the end of the Chemical Bonding unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Build a molecule, then verify with conductivity or solubility.
The student explains why structure dictates behavior (Page 4).
Structures, predictions, and test results kept distinct.
You are making a decision, not adding up points. For each criterion, decide whether the work is Not yet, Approaching, or Mastered — the column language tells you which. A criterion counts as mastered only when the student can both build the model and justify the chemistry behind it. A student carries three tokens per term; one token buys a re-do of one criterion on another day, so a single bad afternoon never sinks the unit.
Accept any answer in the synonyms column — they are pre-approved as equivalent. The third column flags the confusions that look close but are not yet, so you can coach precisely.
| Canonical answer | Accepted synonyms | Common confusion / discriminator |
|---|---|---|
| Bond types | ||
| Ionic bond | electron transfer bond | Metal + nonmetal; large electronegativity difference |
| Covalent bond | shared-electron bond | Nonmetal + nonmetal; small electronegativity difference |
| Electronegativity | electron-pulling power | The difference classifies the bond, not one atom alone |
| Metallic bond | sea of electrons | Delocalized electrons; explains conductivity and malleability |
| Structure & shape | ||
| Lewis structure | electron-dot structure | Show lone pairs and formal charge, not just bonds |
| VSEPR | electron-domain theory | Lone pairs push too — molecular shape ≠ electron geometry |
| Bond polarity | dipole | Polar bonds can cancel by symmetry → nonpolar molecule |
| Resonance | delocalized structure | Not flipping back and forth; an average of structures |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Bond type & electronegativity | Cannot tell ionic from covalent from metallic. | Classifies bonds by element type but not by electronegativity difference. | Uses electronegativity differences to classify bonds and predict each type's properties. |
| Lewis structures | Draws structures with wrong electron counts. | Draws simple molecules but misses lone pairs, formal charge, or resonance. | Draws valid structures including resonance, expanded octets, and correct formal charges. |
| VSEPR & molecular geometry | Cannot name a molecular shape. | Names shapes from a chart without accounting for lone pairs. | Predicts shape and bond angles from electron domains, distinguishing molecular from electron geometry. |
| Polarity & intermolecular consequences | Calls every molecule with polar bonds polar. | Identifies polar bonds but ignores symmetry. | Uses geometry and dipole cancellation to determine overall polarity and predict solubility. |
| Lab technique (model building / conductivity) | Builds models that violate the structure or skips testing. | Builds correct models but cannot link them to a property test. | Builds accurate 3-D models and confirms predictions with a conductivity or solubility test. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
The split between Approaching and Mastered is structure drives property: not just naming a shape, but using it to predict whether the molecule dissolves, conducts, or has a dipole. Ask “so what does that shape do?”
Read these before you grade. They show what Mastered and Not yet actually sound like, plus the edge cases where you should coach rather than decide on the spot.
Student: ______________________________________ Date: _______________ Guide: _________________________
| # | Criterion | Decision | Notes |
|---|---|---|---|
| 1 | Bond type & electronegativity | NY / Appr / Mast | |
| 2 | Lewis structures | NY / Appr / Mast | |
| 3 | VSEPR & molecular geometry | NY / Appr / Mast | |
| 4 | Polarity & intermolecular consequences | NY / Appr / Mast | |
| 5 | Lab technique (model building / conductivity) | NY / Appr / Mast | |
| 6 | Integration (cross-domain) | NY / Appr / Mast |
☐ No ☐ Yes — for criterion: __________ Tokens remaining: ☐ 3 ☐ 2 ☐ 1 ☐ 0
NY = Not yet · Appr = Approaching · Mast = Mastered · Unsure between two levels? Circle the lower one and note what a re-do would need.