Parent plan · Week 3 · Atoms, Electrons & Periodicity — launch — Physical Science: Chemistry
Parent teaching plan · 36 weeksUnits to teach or revisit
Chapter 2 · Atoms, Electrons & Periodicity
- Unit 2.1 · Atomic Models & Subatomic Particles
- Unit 2.2 · Isotopes & Average Atomic Mass
- Unit 2.3 · Electron Configuration
Assigned readings
Develop this chapter question: How does atomic structure explain chemical patterns?
This week’s goals
- Explain models, species, arrows and axes before substituting values.
- Conserve the relevant atoms, charge, amount and energy account.
- Apply independently, state limits and revise from evidence.
Read From a spectrum to an atomic model at chapter launch and revisit it alongside this week’s linked units, figures and investigation.
Five flexible sessions, normally 50–60 minutes. Two core unit sessions are scheduled, with a third for selected demanding topics. Sample week uses a complete 90-minute paper plus about 30 minutes of corrections within two ordinary-hour equivalents.
Session 1 · Atomic Models & Subatomic Particles — build the model
Use the linked chapter reading, unit explanations, figures and notebook.
Your task
Read the chapter background and unit language. Draw a first model, study the core explanation and Parts 1–2, trace each figure and attempt the visual questions/checks. Complete a first worked case with its answer covered.
- Prepare the assigned explanation and identify the question.
- Trace a model or graph, labeling its species and units.
- Attempt the assigned reasoning and calculation before opening guidance.
- Compare with criteria and retain an explained correction.
Hint and response guidance
Name the species, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.
The rare large-angle events constrain how concentrated the positive charge and mass must be; a useful model explains the distribution, not only the most common event. Both have 11 protons. The ion has 10 electrons; ²⁴Na has 13 neutrons rather than 12. Proton count establishes the shared identity.
- Use the supplied evidence and correct species/units.
- Explain the relevant mechanism or relationship.
- Show intermediate working or a labeled model.
- State an assumption, limitation or useful next test.
Session 2 · Atomic Models & Subatomic Particles — apply and explain
Use the linked chapter reading, unit explanations, figures and notebook.
Your task
Study Parts 3–4 and selected source-model prompts, then attempt the whole-unit application, illustrated practice and changed independent case. Explain a correction, revise the opening model and complete the exit check.
- Prepare the assigned explanation and identify the question.
- Trace a model or graph, labeling its species and units.
- Attempt the assigned reasoning and calculation before opening guidance.
- Compare with criteria and retain an explained correction.
Hint and response guidance
Name the species, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.
Z=17, A=35, chlorine with charge −1: ³⁵Cl⁻. Changing neutron number while keeping 17 protons makes another chlorine isotope. Changing only electron number changes its ionization state.
- Use the supplied evidence and correct species/units.
- Explain the relevant mechanism or relationship.
- Show intermediate working or a labeled model.
- State an assumption, limitation or useful next test.
Session 3 · Isotopes & Average Atomic Mass — build the model
Use the linked chapter reading, unit explanations, figures and notebook.
Your task
Read the chapter background and unit language. Draw a first model, study the core explanation and Parts 1–2, trace each figure and attempt the visual questions/checks. Complete a first worked case with its answer covered.
- Prepare the assigned explanation and identify the question.
- Trace a model or graph, labeling its species and units.
- Attempt the assigned reasoning and calculation before opening guidance.
- Compare with criteria and retain an explained correction.
Hint and response guidance
Name the species, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.
The mean averages many atoms with the stated relative frequencies; neither individual modeled isotope needs the average mass. Check that fractions sum to one and that the mean lies between 10.0 and 11.0 u. A result near 1,080 u would fail both scale expectations.
- Use the supplied evidence and correct species/units.
- Explain the relevant mechanism or relationship.
- Show intermediate working or a labeled model.
- State an assumption, limitation or useful next test.
Session 4 · Isotopes & Average Atomic Mass — apply and explain
Use the linked chapter reading, unit explanations, figures and notebook.
Your task
Study Parts 3–4 and selected source-model prompts, then attempt the whole-unit application, illustrated practice and changed independent case. Explain a correction, revise the opening model and complete the exit check.
- Prepare the assigned explanation and identify the question.
- Trace a model or graph, labeling its species and units.
- Attempt the assigned reasoning and calculation before opening guidance.
- Compare with criteria and retain an explained correction.
Hint and response guidance
Name the species, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.
24.6=24.0x+26.0(1−x)=26.0−2.0x, so x=0.70. Fractions are 70% lighter and 30% heavier; 0.70(24.0)+0.30(26.0)=24.6 u.
- Use the supplied evidence and correct species/units.
- Explain the relevant mechanism or relationship.
- Show intermediate working or a labeled model.
- State an assumption, limitation or useful next test.
Session 5 · Electron Configuration — build the model
Use the linked chapter reading, unit explanations, figures and notebook.
Your task
Read the chapter background and unit language. Draw a first model, study the core explanation and Parts 1–2, trace each figure and attempt the visual questions/checks. Complete a first worked case with its answer covered.
- Prepare the assigned explanation and identify the question.
- Trace a model or graph, labeling its species and units.
- Attempt the assigned reasoning and calculation before opening guidance.
- Compare with criteria and retain an explained correction.
Hint and response guidance
Name the species, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.
Four occupy 2p, with two unpaired in the shown ground-state arrangement. Total occupancy is eight including 1s and 2s. One orbital can contain at most two electrons, and Hund’s rule favors distributing the three across the degenerate p orbitals first.
- Use the supplied evidence and correct species/units.
- Explain the relevant mechanism or relationship.
- Show intermediate working or a labeled model.
- State an assumption, limitation or useful next test.
Submit this week
- Labeled first/revised models and intermediate calculations.
- Assigned practice and assessed attempts with explained corrections.
- Investigation record/report when assigned, identifying supplied versus collected data.
Parent / teacher weekly conference
Use actual written work to adjust support. Do not count a copied solution as independent mastery. Extend or redistribute time where needed; home-study records do not certify supervised or mandated laboratory requirements.
- Can each relevant symbol and unit be explained?
- Does the calculation conserve the appropriate quantities?
- Can the learner solve a changed case and explain an assumption?