Matter and Its Properties · SHS1 Chemistry

Lesson notes

Learning Objectives

Indicator: 1.1.1.LI.5 - Identify the main postulates of Dalton’s atomic theory and explain the weaknesses of the theory.

By the end of the lesson, learners can:

State all five postulates of Dalton’s atomic theory in their own words.
Identify at least three weaknesses or limitations of Dalton’s atomic theory and give a reason for each.
Evaluate each postulate against modern evidence about atoms, isotopes and chemical reactions.
Construct a simple model of Dalton’s atom as a solid, indivisible sphere using modelling clay or Styrofoam and label it correctly.
Explain why Dalton’s theory, despite its weaknesses, remains important as a foundation for modern atomic theory.

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Curriculum details

Strand: Physical Chemistry (Strand 1)
Sub-strand: Matter and Its Properties (1.1)
Content standard: 1.1.1.CS.1 - Demonstrate understanding of the scientific practices in chemistry using relevant acquired skills to solve problems as well as explaining the structure of the atom and its stability. 1.1.1.LO.1 Use the knowledge and understanding of the scientific practices in Chemistry to explain the structure of the atom as well as the stability of its nucleus. 1.1.1.LO.2 Use the mole concept to determine the amount and quantity of various substances involved in chemical reactions. 1.1.1.LO.3 Write mole ratios for chemical equations and apply it in quantitative analysis. 1.1.1.LO.4 Use the kinetic theory of matter to explain the behaviour of solids, liquids and gases under different conditions and describe the laboratory preparation of gases as well as their uses in everyday life.
Indicator: 1.1.1.LI.5 - Identify the main postulates of Dalton's atomic theory and explain the weaknesses of the theory.
Suggested placement: Semester 1, Week 5 (Week 5 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: NaCCA curriculum document, p. 28

Exemplars (from the NaCCA curriculum)

Talk for Learning: Review the description of the atom and its sub-atomic particles from JHS syllabus. Group Work: In mixed-ability groups,
- Discuss the Dalton's atomic theory.
- Evaluate and critique each of the postulates of Dalton's atomic theory with the aid of relevant charts or other resources.
Project-Based Learning:
- Construct a model to represent the atom as a simple sphere with no internal structure.
- Draw a diagram of the atom modelled.
- Display the model and diagram for class discussion.
Teaching and Learning Materials:
- * ICT devices * Household items with labels * Chemical containers with labels * Containers having chemical assay * Personal protective equipment (goggles, laboratory coat/apron, hand gloves etc) * * Http://www.kentchemistry.com/links/atomicstructure/PauliHundsRule.htm Hydrogen peroxide * * Http://www.youtube.com.watch?v=2AFPfg0come
- Hydrazine * * Http://www.khanacademy.com Oxidising materials * * Https://www.youtube.com/watch?v=ZIAyNFLRFuw Flammable materials * * https://phet.colorado.edu/en/simulations/rutherford-scattering Acetic acid and nitric acid * * https://www.khanacademy.org/science/chemistry/electronic-structure-of-
- Worksheets with incomplete nuclear reactions with prepared mark schemes * * http//www.youtube.com/watch?v=PpOAlj7sOEc Worksheets of empty orbital diagram for learners to complete * Worksheets with blank column for numbers of proton, neutrons and electrons * Fire extinguisher * Fire blanket * * Charts of hazard, prohibition and mandatory Material for setting fire * * Videos or charts of wrong practices in
- Markers * * Chart of the mass spectrometer Cardboard
- * Potassium permanganate and glycerol * Counters with up and down orientation to represent electron spin-pairing and boxes to represent orbitals * Modelling clay (plasticine) * Clay * Styrofoam * Calculator
- Models: Use One balloon per s orbital, per p-orbital, three (different coloured) subshell of P orbital
- WEBSITES * Chemsketch or simulation for filling atomic
- atoms/history-of-atomic-structure/a/discovery-of-the-electron
- * https://www.khanacademy.org/science/chemistry/electronic-structure-of- atoms/history-of-atomic-structure/v/rutherfords-gold-foil-experiment * Http//www.youtube.com/watch?v=m92QR7CBNoQ
- CHARTS
- * Mass spectrogram for analyses * Charts of experimental set-up of J. J.
- Rutherford's alpha particle scattering * Charts of line and continuous spectra
- Chart showing how the energy levels in series
- two balloons joined at their knots pairs of balloons to make one
- orbitals
- symbols the chemical laboratory
- Thompson's experiment and experiment
- the hydrogen give rise to spectral
Assessment (1.1.1.AS.5). The document marks these depth-of-knowledge levels for this indicator: Level 3 Strategic reasoning.