This is an innovative teaching manual about the topic " Hydrocarbons".

1. Innovative Teaching Manual
Name of the teacher : Geethu K S
Subject : Chemistry
Standard : IX
Unit : The world of carbon
Subunit : Hydrocarbons
Teaching Objectives
• Students are able to explain the concept of hydrocarbons.
• Students are able to draw the hydrocarbon molecules by the number of carbon atoms.
• Students are able to explain the concepts of alkanes, alkenes and alkynes.
• Students are able to classify the hydrocarbon compounds based on the nature of C - C
bonding.
• Students create structural formulas for 10 hydrocarbon molecules.
Important Terms : Carbon, hydrogen, hydrocarbon, alkanes, alkenes, alkynes, bond,
single bond, double bond, triple bond, structural formula, molecule.
Concepts
1. The compounds which contains hydrogen and carbon are collectively called
hydrocarbons.
2. Alkanes are hydrocarbons in which all the bonds are single bonds.
3. Alkenes are hydrocarbons which contain at least one carbon carbon double bond.
4. Alkynes are hydrocarbons which contain at least one carbon carbon triple bond.
First teacher gives a brief description of the class going to take.
Today I am going to teach you a new lesson in the chapter, The world of carbon and is called
hydrocarbons and also the classification of hydrocarbons on the basis of bonding.
Activity l

2. 1. Teacher asks one of the students to come forward and write the symbol of carbon atom on
the black board.
2. Teacher asks another student to fill up the valency with bonds represented as small lines.
3. Again teacher asks another student to connect the all bonds with hydrogen atoms.
The teacher tells students that now we obtain a molecule which contains one carbon and four
hydrogen atoms. And it is called methane.
• Methane is the most simple compound containing hydrogen and carbon. And it is the
simple hydrocarbon.
Teacher asks students following questions
• What is meant by hydrocarbons?
Notes: The compounds which contains hydrogen and carbon are collectively called
hydrocarbons. And the valency of the one carbon atom is four. Thus the four valency of one
carbon is filled with four hydrogens we get the simplest hydrocarbon as shown on the black
board. It is called methane.
Teacher asks students to do the following activities.
• Draw the structure of next hydrocarbon on the black board. (Teacher give some clues that
it contains two carbon atoms and six hydrogens and only exist one C - C bond.)
• Draw the structure of next hydrocarbon with three carbons on the black board.
Notes: To draw the structure of hydrocarbons , each carbon atom has valency four. And out
of these one valencies of each carbon is used to form C - C bond and others are used to form
C - H bond.
Memory points
First draw the C - C bond and then fill the remaining valencies with hydrogen.
Activity II
Teacher asks to observe the figure.
Teacher tells that as you all know that the C - C bond is a covalent bond likewise C - H bond
is also covalent.

3. Teacher asks students following questions
• What are the possible types of bonding exist in the carbons to form bonds between each
other?
Notes: One carbon can form single bonds , double bonds and triple bonds between other
carbon atom. Each carbon atom has four valence electrons. And covalent bonds are formed by
the sharing of valence electrons. Thus carbon can share its three electrons between each
other. And the left one for forming the C - H bond. Because the molecules formed here are
hydrocarbons. So the maximum bonding to exist on all hydrocarbons is three.
Teacher asks students following questions
• How many classifications was made for hydrocarbons on the basis of the nature of C - C
bonding?
Teacher tells that on the basis of the nature of C - C bonding.
• We can classify the hydrocarbons into three.
• These three classifications are called by three different names such as alkane , alkenes
and alkynes respectively.
Teacher asks students following questions
• What is meant by alkanes?
• What is meant by alkanes?
• What is meant by alkynes?
Notes: Alkanes are hydrocarbons in which all the bonds are single bonds. Alkenes are
hydrocarbons which contain at least one carbon carbon double bond. Alkynes are
hydrocarbons which contain at least one carbon carbon triple bond.
Memory points
Alkanes contains only single bonds , alkenes contains at least one C - C double bond and
alkynes contains at least one C - C triple bond.
Assessment
1. What is meant by hydrocarbons?
2. How many classifications was made for hydrocarbons on the basis of the nature of C - C
bonding?

4. 3. What is meant by alkanes?
4. What is meant by alkenes?
5. What is meant by alkynes?
Follow up activity
Draw the structure of first ten hydrocarbons in the increasing order and also draw the
corresponding alkenes and alkynes. Starts with methane.