SHS1 Chemistry · Semester 2 Week 9: Periodicity

Lesson notes

Learning Objectives

Indicator: 1.2.1.LI.2 - Explain how periodic properties change with atomic number and principal quantum number.

By the end of the lesson, learners can:

State the periodic law and explain its meaning in their own words.
Define atomic size, ionic size, ionization energy, electron affinity and electronegativity.
Describe how each periodic property varies across a period (with increasing atomic number) and down a group (with increasing principal quantum number).
Explain the factors (nuclear charge, shielding effect, principal quantum number) that account for the trends in each periodic property.
Account for the discrepancies in the periodic properties involving beryllium, boron, oxygen and nitrogen.

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Curriculum details

Strand: Systematic Chemistry of the Elements (Strand 2)
Sub-strand: Periodicity (2.1)
Content standard: 1.2.1.CS.1 - Demonstrate knowledge and understanding of how periodic properties change with atomic number and principal quantum number. 1.2.1.LO.1 Describe and explain the trends of periodic properties on the periodic table.
Indicator: 1.2.1.LI.2 - Explain how periodic properties change with atomic number and principal quantum number.
Suggested placement: Semester 2, Week 9 (Week 29 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.
Source document note: The official curriculum document has a fault in this entry, so the curriculum text above is transcribed exactly as printed:

exemplars - p.46: the assessment token is visibly printed `1.X21.1.AS.2`; its content is retained under indicator 1.2.1.LI.2 and associated by sequence and table position
Curriculum reference: NaCCA curriculum document, p. 46

Exemplars (from the NaCCA curriculum)

Talk for Learning: State and explain the periodic law.
Collaborative Learning:
- Research and do presentations on each of the periodic properties (atomic size, ionic size, ionization energy, electron affinity and electronegativity).
- The presentations on the periodic properties should cover the following headings: a) The meaning of each periodic property. b) Factors that affect each periodic property. c) The variation of the periodic property in the periodic table.
- Account for discrepancies in the periodic properties with respect to beryllium, boron, oxygen and nitrogen.
Teaching and Learning Materials:
- * Videos on the periodic table * Worksheets to write the electronic configuration of the first thirty elements
- CHARTS * Chart of the periodic table * Flipcharts for group presentations
Assessment (1.2.1.AS.2). The document marks these depth-of-knowledge levels for this indicator: Level 2 Skills of conceptual understanding.