Lesson Note on Sulphur: Meaning, Electronic Structure, Allotropy and Uses for SSS 2

Class: Senior Secondary School 2 (SS2 / SSS2)
Term: 3rd Term
Week: 1
Age: 16 years
Duration: 45 minutes
Subject: Chemistry
Curriculum Theme: Chemistry of Non-metals
Previous Lesson: .
Topic: SULPHUR
Subject Matter: Meaning of sulphur, general properties of group VIA elements, electronic structure of sulphur, allotropes of sulphur, uses of sulphur.

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

• Define sulphur as a non-metal element.
• State three general properties of Group VIA elements.
• Write the electronic configuration of sulphur.
• Explain the term ‘allotropy’.
• Identify the common allotropes of sulphur.
• List three uses of sulphur.

Affective Domain:

• Appreciate the importance of sulphur and its compounds in daily life.
• Show interest in learning about the different forms of elements.

Psychomotor Domain:

• Draw simple diagrams of the crystalline allotropes of sulphur.
• Handle sulphur samples carefully during observation.

Social Domain:

• Participate actively in class discussions about sulphur.
• Collaborate with peers in identifying the uses of sulphur.

Reference Materials

The following resources were used in planning this lesson:

• Senior Secondary Schools Education Curriculum
• State Unified Scheme of Work
• New School Chemistry for Senior Secondary Schools by Osei Yaw Ababio

Instructional Materials

The teacher will teach this lesson with the aid of:

• Chart showing allotropes of sulphur
• Sulphur ointment
• Sulphur pellets or flower of sulphur

Rationale for the Lesson

Sulphur is an important element with various industrial and biological uses. Understanding its properties and different forms helps pupils appreciate its significance in chemistry and everyday applications.

Prerequisite/Previous Knowledge

Pupils have prior knowledge of elements, the periodic table, atomic structure, and electronic configuration from Junior Secondary School and previous SS classes.

Lesson Content/Board Summary

Sulphur

Meaning of Sulphur

Sulphur is a yellow non-metal element found in Group VIA (Group 16) of the periodic table. Its atomic number is 16 and its chemical symbol is S.

General Properties of Group VIA Elements (Chalcogens)

The following are general properties of Group VIA elements:

• They are known as chalcogens (ore-forming elements).
• They have 6 valence electrons.
• They tend to gain 2 electrons to form S²⁻ ions or share electrons to form covalent compounds.
• They exhibit varying oxidation states, commonly -2, +2, +4, +6.
• They show a transition from non-metallic to metallic character down the group.
• Their atomic radius increases down the group.
• Their electronegativity decreases down the group.

Electronic Structure of Sulphur

The atomic number of Sulphur (S) is 16.

Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁴

Valence electrons: 6 (in the 3rd shell)

Allotropy and Allotropes of Sulphur

Allotropy: This is the existence of an element in two or more different forms in the same physical state. These forms are called allotropes. Allotropes have different physical properties but similar chemical properties.

The following are common allotropes of sulphur:

• Rhombic Sulphur (α-sulphur):
  • Stable below 96°C.
  • Octahedral crystals.
  • Yellow in colour.
  • Insoluble in water, soluble in carbon disulphide (CS₂).
  • Made of S₈ rings.
• Monoclinic Sulphur (β-sulphur):
  • Stable above 96°C.
  • Needle-like crystals.
  • Pale yellow in colour.
  • Insoluble in water, soluble in carbon disulphide (CS₂).
  • Also made of S₈ rings.
• Plastic/Amorphous Sulphur:
  • Formed by pouring molten sulphur into cold water.
  • Rubber-like, elastic, and dark brown.
  • Not crystalline, consists of long chains of sulphur atoms.
  • Unstable and slowly reverts to rhombic sulphur.
  • Insoluble in carbon disulphide.

Uses of Sulphur

The following are uses of sulphur:

• Manufacture of sulphuric acid (H₂SO₄).
• Vulcanization of rubber (improves elasticity and strength).
• Manufacture of matches, gunpowder, and fireworks.
• Production of fungicides and insecticides.
• Preparation of sulphur drugs (e.g., sulfa drugs).
• Used in medicine for skin ointments (e.g., sulphur ointment for scabies).
• Bleaching of wool and silk.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils, reminds them of the periodic table, and asks them to name some elements they know.
Pupils’ Activity: Pupils respond to greetings and name elements like oxygen, nitrogen, etc.
Learning Point: Pupils connect prior knowledge to the new topic.

Step 2: Meaning of Sulphur and Group VIA Properties

Time: 7 minutes
Teaching Skill: Explanation/Lecture
Teacher’s Activity: The teacher explains what sulphur is, its position in the periodic table, and discusses the general properties of Group VIA elements.
Pupils’ Activity: Pupils listen attentively and take notes on the definitions and properties.
Learning Point: Pupils understand the definition of sulphur and its group characteristics.

Step 3: Electronic Structure of Sulphur

Time: 7 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher guides pupils to write the electronic configuration of sulphur on the board, emphasizing its valence electrons.
Pupils’ Activity: Pupils write down the electronic configuration in their notebooks and identify the valence electrons.
Learning Point: Pupils can determine the electronic structure of sulphur.

Step 4: Allotropy

Time: 7 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher explains the concept of allotropy, defining it clearly and giving examples of other elements that exhibit allotropy.
Pupils’ Activity: Pupils listen and ask questions for clarification regarding the concept of allotropy.
Learning Point: Pupils understand what allotropy means.

Step 5: Allotropes of Sulphur

Time: 7 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher uses charts and samples (sulphur pellets/flower of sulphur) to explain and show the different allotropes of sulphur and their key properties.
Pupils’ Activity: Pupils observe the chart and samples, identify the allotropes, and note their properties.
Learning Point: Pupils can identify and describe the different allotropes of sulphur.

Step 6: Uses of Sulphur

Time: 5 minutes
Teaching Skill: Discussion/Explanation
Teacher’s Activity: The teacher discusses the various uses of sulphur with the pupils, showing sulphur ointment as a practical example.
Pupils’ Activity: Pupils list and discuss the practical applications of sulphur.
Learning Point: Pupils know the practical applications of sulphur.

Step 7: Evaluation/Review

Time: 5 minutes
Teaching Skill: Questioning/Assessment
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. Define sulphur.
2. State three general properties of Group VIA elements.
3. Write the electronic configuration of sulphur.
4. What is allotropy?
5. Mention two allotropes of sulphur and one property of each.
6. List three uses of sulphur.

Pupils’ Activity: Pupils answer orally and in writing.
Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key learning points of the lesson and assigns homework, asking pupils to research more uses of sulphur.
Pupils’ Activity: Pupils listen, ask further questions if any, and copy the homework.
Learning Point: Reinforces key concepts and prepares for independent study.

Lesson Keywords

• Sulphur – A yellow non-metal element in Group VIA of the periodic table.
• Non-metal – An element that does not have the properties of a metal.
• Group VIA – The group in the periodic table containing oxygen, sulphur, selenium, tellurium, and polonium, also known as chalcogens.
• Chalcogen – A member of Group VIA (Group 16) of the periodic table, meaning “ore-forming”.
• Electronic configuration – The arrangement of electrons in the orbitals of an atom.
• Allotropy – The existence of an element in two or more different forms in the same physical state.
• Allotropes – The different forms of an element that exhibit allotropy.
• Rhombic sulphur – An octahedral crystalline allotrope of sulphur, stable below 96°C.
• Monoclinic sulphur – A needle-like crystalline allotrope of sulphur, stable above 96°C.
• Plastic sulphur – An amorphous, rubber-like allotrope of sulphur.
• Vulcanization – A chemical process for converting natural rubber into more durable materials by adding sulphur.

Differentiation

For pupils who grasp concepts quickly, the teacher can provide additional research questions on the industrial production of sulphur or the chemistry of its compounds. For pupils needing more support, the teacher can use simplified diagrams and spend more time explaining the properties of each allotrope, providing direct examples of sulphur in everyday items.

Note for teachers using this lesson plan

Ensure that the instructional materials, especially the chart of allotropes and actual samples of sulphur (if available), are clearly visible and accessible to all pupils. Encourage pupils to ask questions and participate actively. Emphasize the safety precautions when handling any chemicals in the laboratory.