Periodicity · SHS2 Chemistry

Lesson notes

Learning Objectives

Indicator: 2.2.1.LI.1 - Describe the patterns in physical and chemical properties of the period 3 elements.

By the end of the lesson, learners can:

Describe the trend in metallic character across period 3 (sodium to argon) and explain it using electron configuration and nuclear charge.
Plot a graph of given data on melting points, boiling points or densities of period 3 elements and deduce the trends from the graph.
Predict and describe the physical properties (density, melting point, boiling point, hardness) of period 3 elements based on their position in the periodic table.
Compare the chemical behaviour of period 3 elements in their reactions with water, air or oxygen, acids and chlorine, and write balanced equations for these reactions.
Explain the general trend in reactivity of metals versus non-metals across period 3 using the concepts of ionisation energy, electronegativity and atomic radius.

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Curriculum details

Strand: Systematic Chemistry of the Elements (Strand 2)
Sub-strand: Periodicity (2.1)
Content standard: 2.2.1.CS.1 - Demonstrate understanding of the regular patterns of chemical and physical properties of elements and their compounds in the periodic table. 2.2.1.LO.1 Predict and describe the trends of chemical and physical properties of elements and their compounds in the periodic table. 2.2.1.LO.2 Predict and describe the physical and chemical properties of the halogens as well as their uses in everyday life.
Indicator: 2.2.1.LI.1 - Describe the patterns in physical and chemical properties of the period 3 elements.
Suggested placement: Semester 2, Week 4 (Week 24 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. 76

Exemplars (from the NaCCA curriculum)

Talk for Learning: With the aid of charts, videos or books, discuss trends in the properties of period 3 elements including: a. Metallic property, b. Physical properties (density, melting point and boiling point, hardness). c. Chemical properties (reaction with some common reagents, example, water, acids, alkalis air or oxygen, chlorine)
Digital Learning: Research on the internet or watch videos on the reactions of period 3 elements.
Problem-Based Learning: Plot a graph of physical properties from given data and use it to deduce trends in physical properties of the elements in period 3.
Teaching and Learning Materials:
- * ICT tools * Textbooks * * Source of heat Graph sheets to plot given data * * Lime water Worksheets
- * Samples of the carbonates and nitrates of Li, Na, K, Mg and Ca
- * Delivery * Test tubes
- Test tube
- tube
- holder
Assessment (2.2.1.AS.1). The document marks these depth-of-knowledge levels for this indicator: Level 2 Skills of conceptual understanding.