Chemical Symbols, Formulae, Equations and Common Element Symbols for SS 1

Class: SS 1
Term: First Term
Week: 9
Age: 15 years
Duration: 60 minutes
Subject: Chemistry
Curriculum Theme: The Chemical World
Focal competence: Using symbols, formulae and equations to express the composition and interactions between elements and compounds
Key competencies/values: Critical Thinking
Skills:

• Calculating mass of atomic numbers and valencies of elements from symbols and formulae
• Balancing of chemical equations

Previous Lesson: Proper ways of handling, storing and disposing of chemicals
Topic: Symbols, Formulae And Equations
Subject Matter: Meanings of chemical symbols, formulae and equations, Names and chemical symbols of the first 20 elements on the Periodic Table, Names and symbols of other common elements

Specific Objectives

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

Cognitive Domain

• Define chemical symbols, formulae, valencies, equations, empirical formulae, and molecular formulae.
• Identify the first 20 elements on the Periodic Table.
• Write the symbols of the first 20 elements and other common elements.
• Write the chemical formula of common substances.
• Distinguish between chemical symbols and chemical formulae.

Affective Domain

• Appreciate the importance of chemical symbols and formulae in communicating chemical information.
• Show accuracy and attention to detail when writing chemical symbols and formulae.

Psychomotor Domain

• Correctly use a Periodic Table to locate elements and their symbols.
• Construct simple chemical formulae for common compounds.

Social Domain

• Collaborate effectively in pairs to identify elements and their symbols from the Periodic Table.

Reference Materials

The following resources were used in planning this lesson:

• 2025 New Revised Senior Secondary Education Curriculum (SSEC)
• Relevant State Unified Scheme of Work
• The HeadTeacher Scheme of work For The New Revised Senior Secondary Education Curriculum (SSEC)

Instructional Materials

The teacher will teach this lesson with the aid of:

• Periodic Table (large wall chart and smaller versions for students)
• Atomic structure models (optional, for visual aid)
• Projector (if available, for displaying elements and symbols)
• Internet (for accessing visual aids if projector is used)
• Cardboard (for making flashcards of elements and symbols)
• Whiteboard and markers
• Textbooks

Rationale for the Lesson

This lesson provides the foundational knowledge for understanding chemical composition and reactions. Mastering chemical symbols, formulae, and equations is essential for interpreting chemical information and communicating effectively in Chemistry. It helps students grasp how elements combine to form compounds and how these compounds interact in chemical processes.

Prerequisite/Previous Knowledge

Students should have a basic understanding of what elements and compounds are, and a general idea of the structure of an atom from their JSS Science classes.

Lesson Content/Board Summary

Symbols, Formulae And Equations

Chemical Symbols

A chemical symbol is a shorthand notation used to represent an element. Each element has a unique symbol, which is usually derived from its English or Latin name.

1. Symbols are usually one or two letters.
2. The first letter is always capitalised, and the second letter (if any) is always lowercase.
3. Symbols represent one atom of the element.

Chemical Formulae

A chemical formula is a shorthand representation of a chemical compound or molecule, showing the types of atoms and their numerical proportions.

1. Formulae indicate the elements present in a compound and the ratio in which they are combined.
2. Subscripts are used to indicate the number of atoms of each element in a molecule or formula unit.

Distinction between Symbols and Formulae

1. Symbols represent individual elements (e.g., H for Hydrogen, O for Oxygen).
2. Formulae represent compounds or molecules made up of two or more atoms (e.g., H₂O for water, CO₂ for carbon dioxide).

Valency

Valency is the combining power of an element. It represents the number of hydrogen atoms that can combine with or be replaced by one atom of the element.

1. Elements in the same group of the Periodic Table often have the same valency.
2. Valency helps in writing chemical formulae.

Chemical Equations

A chemical equation is a symbolic representation of a chemical reaction, showing the reactants and products involved. It uses chemical formulae and symbols to describe the changes that occur.

1. Reactants are written on the left side of the arrow.
2. Products are written on the right side of the arrow.
3. The arrow indicates the direction of the reaction.

Empirical Formulae

An empirical formula shows the simplest whole-number ratio of atoms of each element in a compound. It represents the lowest possible ratio of elements.

1. For example, the empirical formula for glucose (C₆H₁₂O₆) is CH₂O.

Molecular Formulae

A molecular formula shows the actual number of atoms of each element in a molecule of a compound. It gives the exact composition of one molecule.

1. For example, the molecular formula for glucose is C₆H₁₂O₆.

Names and Chemical Symbols of the First 20 Elements

The first 20 elements on the Periodic Table and their symbols are:

1. Hydrogen – H
2. Helium – He
3. Lithium – Li
4. Beryllium – Be
5. Boron – B
6. Carbon – C
7. Nitrogen – N
8. Oxygen – O
9. Fluorine – F
10. Neon – Ne
11. Sodium – Na
12. Magnesium – Mg
13. Aluminium – Al
14. Silicon – Si
15. Phosphorus – P
16. Sulphur – S
17. Chlorine – Cl
18. Argon – Ar
19. Potassium – K
20. Calcium – Ca

Names and Symbols of Other Common Elements

Some other common elements and their symbols include:

1. Iron – Fe (from Latin: Ferrum)
2. Copper – Cu (from Latin: Cuprum)
3. Zinc – Zn
4. Silver – Ag (from Latin: Argentum)
5. Gold – Au (from Latin: Aurum)
6. Lead – Pb (from Latin: Plumbum)
7. Mercury – Hg (from Latin: Hydrargyrum)
8. Tin – Sn (from Latin: Stannum)
9. Bromine – Br
10. Iodine – I

Writing Chemical Formulae of Common Substances

To write a chemical formula, we use the symbols of the elements and their valencies. The valencies are exchanged and written as subscripts.

Example 1: Water

1. Hydrogen (H) has a valency of 1.
2. Oxygen (O) has a valency of 2.
3. Exchange valencies: H₂O₁.
4. Simplify: H₂O.

Example 2: Carbon Dioxide

1. Carbon (C) has a valency of 4.
2. Oxygen (O) has a valency of 2.
3. Exchange valencies: C₂O₄.
4. Simplify the ratio (divide by 2): CO₂.

Example 3: Sodium Chloride

1. Sodium (Na) has a valency of 1.
2. Chlorine (Cl) has a valency of 1.
3. Exchange valencies: Na₁Cl₁.
4. Simplify: NaCl.

Teaching Methods/Instructional Techniques

Discussion, Explanation, Question and Answer, Guided Practice, Pair Work, Individual Practice, Demonstration

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Recalling/Engaging

Teacher’s Activity: The teacher greets the students and asks them to recall what they know about elements and compounds from their previous classes. The teacher then introduces the topic: Chemical Symbols, Formulae, and Equations, explaining that these are the language of Chemistry.

Pupils’ Activity: Pupils respond to questions about elements and compounds and listen attentively to the introduction.

Learning Point: Introduction to chemical language

Step 2: Meaning of Chemical Symbols

Time: 10 minutes

Teaching Skill: Explanation/Definition

Teacher’s Activity: The teacher defines chemical symbols, explaining their purpose as shorthand notations for elements. The teacher uses examples like ‘H’ for Hydrogen and ‘O’ for Oxygen, highlighting the rules for writing symbols (first letter capital, second letter small).

Pupils’ Activity: Pupils listen, ask questions for clarification, and copy the definition and examples of chemical symbols.

Learning Point: Definition of chemical symbols

Step 3: Meaning of Chemical Formulae and Distinction from Symbols

Time: 10 minutes

Teaching Skill: Explanation/Differentiation

Teacher’s Activity: The teacher defines chemical formulae, giving examples like H₂O and CO₂. The teacher then clearly differentiates between a chemical symbol (representing an element) and a chemical formula (representing a compound or molecule), using a comparison table or examples on the board.

Pupils’ Activity: Pupils listen, observe the examples, and note the distinction between symbols and formulae.

Learning Point: Formulae and symbol distinction

Step 4: Meaning of Valency and Chemical Equations

Time: 5 minutes

Teaching Skill: Explanation/Concept Introduction

Teacher’s Activity: The teacher defines valency as the combining power of an element and briefly explains how it helps in writing formulae. The teacher also defines chemical equations as symbolic representations of chemical reactions, mentioning reactants and products.

Pupils’ Activity: Pupils listen and note down the definitions of valency and chemical equations.

Learning Point: Valency and equation definitions

Step 5: Identifying and Writing Symbols of the First 20 Elements

Time: 10 minutes

Teaching Skill: Guided Practice/Identification

Teacher’s Activity: The teacher displays a large Periodic Table. The teacher guides students in pairs to use smaller Periodic Tables to identify, name, and write the symbols of the first twenty (20) elements. The teacher walks around, providing support and checking their work.

Pupils’ Activity: Pupils work in pairs, using the Periodic Table to identify and write the names and symbols of the first 20 elements.

Learning Point: First 20 elements’ symbols

Step 6: Identifying and Writing Symbols of Other Common Elements & Writing Formulae

Time: 5 minutes

Teaching Skill: Guided Practice/Application

Teacher’s Activity: The teacher introduces other common elements like Iron (Fe), Copper (Cu), Silver (Ag), etc., and their symbols. The teacher then guides students through examples of writing chemical formulae for common substances like water (H₂O) and sodium chloride (NaCl) using valencies.

Pupils’ Activity: Pupils identify and write symbols for other common elements and practice writing simple chemical formulae.

Learning Point: Common elements and formulae

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. What is a chemical symbol?
2. Give two examples of chemical symbols.
3. What is the difference between a chemical symbol and a chemical formula?
4. Write the chemical symbol for Potassium and Iron.
5. What is the chemical formula for water?

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Understanding symbols and formulae

Step 8: Note-Taking

Time: 10 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils/students to copy the essential Board Summary notes, including definitions, element lists, and examples of formulae, into their notebooks.

Pupils’ Activity: Pupils/students copy the notes carefully into their notebooks.

Learning Point: Recording lesson information

Step 9: Conclusion

Time: 5 minutes

Teaching Skill: Summarising

Teacher’s Activity: The teacher summarises the key points of the lesson, reiterating the importance of symbols, formulae, and equations as the universal language of Chemistry. The teacher encourages students to continue practicing writing symbols and formulae.

Pupils’ Activity: Pupils listen to the summary and ask any final questions.

Learning Point: Consolidation of key concepts

Continuous Assessment/Further Study

Type: Homework

Instruction: Answer the following questions in your Chemistry notebook.

1. Define empirical formula and molecular formula with one example each.
2. Write the names of the elements represented by the following symbols: Na, Mg, Al, Si, P.
3. Write the chemical symbols for the following elements: Sulphur, Chlorine, Argon, Potassium, Calcium.
4. Using the concept of valency, write the chemical formula for:
   1. Magnesium Oxide (Mg valency 2, O valency 2)
   2. Aluminium Oxide (Al valency 3, O valency 2)

Lesson Keywords

• Symbol – Shorthand notation for an element
• Formula – Shorthand notation for a compound or molecule
• Equation – Symbolic representation of a chemical reaction
• Valency – Combining power of an element
• Empirical Formula – Simplest whole-number ratio of atoms in a compound
• Molecular Formula – Actual number of atoms of each element in a molecule
• Element – Pure substance consisting of only one type of atom

Differentiation

For students who grasp concepts quickly, encourage them to research the Latin origins of more element symbols (e.g., Gold, Silver, Lead). For students needing more support, provide flashcards with element names on one side and symbols on the other for repetitive practice. Pair stronger students with weaker ones during group activities.

Suggested Lesson Videos

Search YouTube for “Chemical Symbols and Formulae for SS1 Chemistry” or “Introduction to Chemical Equations for Senior Secondary School”.