Class: Senior Secondary School 2 (SS2 / SSS2)
Term: 2nd Term
Week: 4
Age: 16 years
Duration: 45 minutes
Subject: Chemistry
Curriculum Theme: Elements and their Properties
Previous Lesson: Air: Meaning, Composition, Properties and Flame.
Topic: HYDROGEN
Subject Matter: Meaning of hydrogen (the first element, a light gas with atomic number 1), configuration and possible oxidation numbers, isotopes of hydrogen, unique position of hydrogen in the periodic table, laboratory preparation of hydrogen, industrial preparation of hydrogen, physical and chemical properties of hydrogen, uses of hydrogen.

Specific Objectives

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

Cognitive Domain:

Define hydrogen and state its atomic number.
Explain the electronic configuration of hydrogen.
Identify the isotopes of hydrogen.
Describe the unique position of hydrogen in the periodic table.
Outline the laboratory and industrial preparation methods for hydrogen.
List the physical and chemical properties of hydrogen.
Enumerate the uses of hydrogen.

Affective Domain:

Appreciate the importance of hydrogen in various applications.
Demonstrate a positive attitude towards laboratory safety during experiments.

Psychomotor Domain:

Draw the electronic configuration of hydrogen and its isotopes.
Sketch the apparatus for the laboratory preparation of hydrogen.
Perform simple tests to identify hydrogen gas.

Participate actively in class discussions about hydrogen.
Collaborate effectively during group activities related to hydrogen experiments.

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
Essentials of Chemistry for Senior Secondary Schools by O.A. Adeoye

Instructional Materials

The teacher will teach this lesson with the aid of:

Periodic table
Charts showing a hydrogen balloon and welders at work
Laboratory apparatus for preparation of hydrogen (test tubes, thistle funnel, delivery tube, gas jar, trough, retort stand, zinc granules, dilute sulphuric acid)
Litmus paper, splint

Rationale for the Lesson

This lesson helps pupils understand hydrogen as the first and lightest element, which is important for understanding basic chemistry and its role in various industrial and daily life applications. Understanding hydrogen’s properties and preparation methods provides foundational knowledge for further chemical studies.

Prerequisite/Previous Knowledge

Pupils should have prior knowledge of elements, atomic structure, the periodic table, and basic laboratory safety procedures.

Lesson Content/Board Summary

HYDROGEN

1. Meaning and Electronic Configuration

Hydrogen is the first element in the periodic table with atomic number 1. It is the lightest gas known. Its electronic configuration is 1s¹, meaning it has one electron in its outermost shell.

Hydrogen can exhibit oxidation states of +1 (by losing its electron) or -1 (by gaining an electron to complete its duplet).

2. Isotopes of Hydrogen

Isotopes are atoms of the same element with the same atomic number but different mass numbers due to varying numbers of neutrons.

The three isotopes of hydrogen are:

Protium (¹H) – No neutrons (1 proton, 0 neutrons, 1 electron). Most common isotope.
Deuterium (²H or D) – One neutron (1 proton, 1 neutron, 1 electron). Also known as heavy hydrogen.
Tritium (³H or T) – Two neutrons (1 proton, 2 neutrons, 1 electron). It is radioactive.

All isotopes of hydrogen have the same electronic configuration (1s¹) as they have the same number of electrons.

3. Unique Position of Hydrogen in the Periodic Table

Hydrogen occupies a unique position because it shares properties with both Group 1 (alkali metals) and Group 17 (halogens).

Similarities with Group 1: It has one electron in its outermost shell and can lose it to form a positive ion (H⁺).
Similarities with Group 17: It is a non-metal, a gas, and can gain one electron to complete its duplet, forming a hydride ion (H^–).

4. Laboratory Preparation of Hydrogen

Hydrogen is prepared in the laboratory by the reaction of an active metal (e.g., zinc) with a dilute non-oxidizing acid (e.g., dilute sulphuric acid or hydrochloric acid).

Equation:

Zn_(s) + H₂SO_4(aq) → ZnSO_4(aq) + H_2(g)

Procedure:
Zinc granules are placed in a flat-bottomed flask. Dilute sulphuric acid is added through a thistle funnel. Hydrogen gas is collected by downward displacement of water.

Test for Hydrogen:
Hydrogen gas extinguishes a glowing splint with a ‘pop’ sound.

Safety Precautions:
Ensure the apparatus is airtight to prevent gas leakage. Do not use concentrated acids or very reactive metals like sodium or potassium, which react explosively.

5. Industrial Preparation of Hydrogen

Large quantities of hydrogen are prepared industrially by:

Steam reforming of natural gas (methane):
CH_4(g) + H₂O_(g) → CO_(g) + 3H_2(g) (at high temperature and pressure with a catalyst)
Electrolysis of water:
2H₂O_(l) → 2H_2(g) + O_2(g) (using an electrolyte like dilute H₂SO₄)

6. Physical Properties of Hydrogen

Hydrogen is:

A colorless, odorless, and tasteless gas.
The lightest known substance.
Slightly soluble in water.
Neutral to litmus paper.
Has a very low boiling point (-253 °C) and melting point (-259 °C).

7. Chemical Properties of Hydrogen

Combustion: Burns in air or oxygen with a pale blue flame to form water.
2H_2(g) + O_2(g) → 2H₂O_(l)
Reducing Agent: Reduces oxides of less reactive metals to the metal when heated.
CuO_(s) + H_2(g) → Cu_(s) + H₂O_(l)
Reaction with Halogens: Reacts with halogens to form hydrogen halides.
H_2(g) + Cl_2(g) → 2HCl_(g) (in the presence of light)
Hydrogenation: Reacts with unsaturated organic compounds (e.g., alkenes, alkynes) in the presence of a catalyst (e.g., Ni) to form saturated compounds.

8. Uses of Hydrogen

Hydrogen is used in:

The Haber process for the industrial production of ammonia (NH₃).
The hydrogenation of vegetable oils to produce margarine and other solid fats.
As a rocket fuel, especially liquid hydrogen.
Filling meteorological balloons and airships (though helium is safer).
Welding (oxy-hydrogen flame produces very high temperatures).
Fuel cells for generating electricity.
Production of hydrochloric acid.

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 and asks questions about elements in the periodic table, asking them to identify the first element.
Pupils’ Activity: Pupils respond to the greetings and identify hydrogen as the first element.
Learning Point: Pupils recall prior knowledge of elements and the periodic table.

Step 2: Meaning and Electronic Configuration

Time: 5 minutes
Teaching Skill: Explanation/Modeling
Teacher’s Activity: The teacher explains the meaning of hydrogen, its atomic number, and guides pupils to write and draw its electronic configuration.
Pupils’ Activity: Pupils listen, ask questions, and write down the electronic configuration of hydrogen.
Learning Point: Pupils understand the basic definition and atomic structure of hydrogen.

Step 3: Isotopes and Unique Position

Time: 7 minutes
Teaching Skill: Explanation/Discussion
Teacher’s Activity: The teacher explains the concept of isotopes, names the isotopes of hydrogen, and discusses hydrogen’s unique position in the periodic table.
Pupils’ Activity: Pupils listen, take notes, and contribute to the discussion on hydrogen’s position.
Learning Point: Pupils identify hydrogen’s isotopes and understand its classification challenges.

Step 4: Laboratory Preparation

Time: 10 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher demonstrates the laboratory preparation of hydrogen using zinc and dilute sulphuric acid, explaining the setup, reaction, collection, and safety precautions.
Pupils’ Activity: Pupils observe the demonstration, note the chemical equation, and understand the safety aspects.
Learning Point: Pupils learn how to prepare hydrogen in the laboratory and its test.

Step 5: Industrial Preparation and Physical Properties

Time: 5 minutes
Teaching Skill: Lecture/Explanation
Teacher’s Activity: The teacher explains the industrial methods of hydrogen preparation and lists its physical properties.
Pupils’ Activity: Pupils listen attentively and write down the industrial methods and physical properties.
Learning Point: Pupils understand large-scale production methods and characteristics of hydrogen.

Step 6: Chemical Properties

Time: 5 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher performs simple experiments (e.g., burning hydrogen) to show its chemical properties and explains others like reduction and reaction with halogens.
Pupils’ Activity: Pupils observe the experiments and note down the chemical properties and relevant equations.
Learning Point: Pupils understand the reactive nature of hydrogen.

Step 7: Evaluation/Review

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

Define hydrogen and state its atomic number.
Name the three isotopes of hydrogen.
Why is hydrogen considered to have a unique position in the periodic table?
Write the balanced chemical equation for the laboratory preparation of hydrogen using zinc and dilute sulphuric acid.
Mention three industrial uses of hydrogen.

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

Step 8: Conclusion

Time: 3 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson and gives homework, asking pupils to draw the laboratory setup for hydrogen preparation.
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: Pupils reinforce their understanding and prepare for further study.

Lesson Keywords

Hydrogen – The first element with atomic number 1, the lightest gas.
Isotopes – Atoms of the same element with different mass numbers.
Protium – The most common isotope of hydrogen, with no neutrons.
Deuterium – An isotope of hydrogen with one neutron, also known as heavy hydrogen.
Tritium – A radioactive isotope of hydrogen with two neutrons.
Oxidation number – The charge an atom would have if electrons were transferred completely.
Steam reforming – An industrial process to produce hydrogen from natural gas and steam.
Hydrogenation – The chemical process of adding hydrogen to unsaturated compounds.
Reducing agent – A substance that causes another substance to gain electrons (be reduced) and is itself oxidized.

Differentiation

For struggling learners, the teacher will provide simplified notes and visual aids, allowing them to focus on defining key terms and identifying the main uses. Advanced learners will be challenged with questions requiring deeper analysis of hydrogen’s reactivity and its role in complex industrial processes, such as discussing the energy implications of hydrogen as a fuel source.

Note for teachers using this lesson plan

Ensure all safety precautions are strictly observed during the demonstration of hydrogen preparation and testing. Encourage active participation and critical thinking. Use the periodic table and charts effectively to enhance understanding. Emphasize the practical applications of hydrogen to make the lesson relatable.