Periodicity · SHS2 Chemistry

Lesson notes

Learning Objectives

Indicator: 2.2.1.LI.2 - Describe the patterns in physical and chemical properties of compound (hydrides, oxides, hydroxides and chlorides) of period 3 elements.

By the end of the lesson, learners can:

Classify the hydrides, oxides, hydroxides and chlorides of period 3 elements as ionic or covalent based on their structure and bonding.
Predict and describe the acid-base character of the oxides, hydroxides and chlorides of period 3 elements, moving from basic through amphoteric to acidic across the period.
Write balanced chemical equations for the reactions of period 3 compounds with water, including the hydrolysis of chlorides and the formation of alkaline or acidic solutions.
Describe and explain the trend in thermal stability of the carbonates and nitrates of period 2 and 3 elements using the polarising power of the cation.
Compare the physical properties (melting point, electrical conductivity, solubility) of the compounds of period 3 elements and account for the trends in terms of structure and bonding.

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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.2 - Describe the patterns in physical and chemical properties of compound (hydrides, oxides, hydroxides and chlorides) of period 3 elements.
Suggested placement: Semester 2, Week 5 (Week 25 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 Approach: Using think-pair-share approach, predict and describe the physical properties of the compounds of the period three elements. a. Hydrides: structure and bonding, acid-base characteristics, their reaction with water and air. b. Oxides: structure and bonding, acid-base characteristics, hydrolytic behaviour and solubility in water. c. Hydroxides: types, structure and bonding, acid-base characteristics. d. Chlorides: types, structure and bonding, acid base characteristics, reaction in water and air.
Collaborative Learning:
- In small groups, discuss the thermal stability of carbonates (CO 32-) and nitrates (NO ) of 3- period two and three elements to include Li, K and Ca and account for their differences.
- Write chemical equations to show how the compounds decompose on heating.
Experiential Learning:
- Perform simple experiments to compare the thermal stabilities of Na CO , K CO and 2 3 2 3 CaCO . 3
- Test for any gas that evolves.
- Write balanced chemical equations of the reactions that take place.
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.2). The document marks these depth-of-knowledge levels for this indicator: Level 3 Strategic reasoning.