This packet is everything a parent or guide needs to assess Unit 01 at home — the 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 running the lab and reasoning from electron structure aloud.
By the end of the Atomic Structure unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Emission colors linked to electron transitions — observed live.
The student reasons from electron structure aloud (Page 4 anchors).
Contemporaneous record of flame colors, spectra, and the unknown ID.
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 run the technique and justify the atomic 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 |
|---|---|---|
| The atom & notation | ||
| Atomic number | proton number; Z | Defines the element; never changes for a given element |
| Mass number | protons + neutrons; A | Not the same as atomic mass on the table (that is a weighted average) |
| Isotope | same element, different neutrons | Different mass number, same atomic number |
| Ion | charged atom; cation / anion | Charge comes from electrons gained/lost, not protons |
| Electrons & orbitals | ||
| Electron configuration | orbital filling; e⁻ arrangement | Follows Aufbau order; 4s fills before 3d |
| Valence electrons | outer-shell electrons | Drive bonding; set by the group number for main-group elements |
| Ground state | lowest-energy arrangement | Excited state = an electron bumped up a level (the flame-test cause) |
| Hund’s rule | one per orbital first | Fill singly before pairing within a sublevel |
| Periodic trends | ||
| Effective nuclear charge | Zeff; net pull on outer e⁻ | The “why” behind every trend on the table |
| Atomic radius | atom size | Decreases left-to-right; increases top-to-bottom |
| Ionization energy | energy to remove an electron | Opposite trend to radius — smaller atom, harder to ionize |
| Electronegativity | pull on shared electrons | Highest near fluorine, top-right (excluding noble gases) |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Subatomic particles & atomic notation | Confuses protons, neutrons, and electrons or their charges. | Names the particles but stumbles on mass number vs. atomic number. | Reads any isotope symbol fluently and states protons, neutrons, electrons, charge. |
| Isotopes & average atomic mass | Thinks all atoms of an element are identical. | Defines isotopes but cannot weight a mass average. | Calculates average atomic mass from abundances and explains the non-whole number. |
| Electron configuration & orbitals | Writes configurations as random letters and numbers. | Fills orbitals but violates Hund’s rule or the Aufbau order. | Writes ground-state, noble-gas, and orbital diagrams correctly, including Cr and Cu. |
| Periodic trends | Cannot state whether a property rises or falls across a period. | Recalls a trend’s direction but not its cause. | Predicts and ranks radius, ionization energy, electronegativity using Zeff and shielding. |
| Lab technique (flame tests / spectra) | Skips or contaminates the flame-test loop. | Runs the test but misassigns colors to elements. | Performs clean flame tests, links colors to electron transitions, identifies an unknown. |
| Integration (cross-domain) | Treats the science as isolated facts. | Names a link to history, reading, or writing but cannot defend it. | Connects the unit across History · Reading · Writing and defends why it matters. |
Work down the criteria one at a time. Ask the student to reason it out rather than recall — “why is chlorine smaller than silicon?” The cause (effective nuclear charge, shielding) is where Approaching and Mastered separate. Reading the table is Approaching; explaining why the table looks that way is Mastered.
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 | Subatomic particles & atomic notation | NY / Appr / Mast | |
| 2 | Isotopes & average atomic mass | NY / Appr / Mast | |
| 3 | Electron configuration & orbitals | NY / Appr / Mast | |
| 4 | Periodic trends | NY / Appr / Mast | |
| 5 | Lab technique (flame tests / spectra) | 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.