Alkenes

It is a hydrocarbon in which carbon atoms are connected by double bonds .

Example: Ethene

  • Formula of Ethene is C 2 H 4 .
  • There is 1 double bond between 2 Carbon atoms.
  • Since Carbon has 4 valence electrons and only 2 of them are shared by other carbon atom, the remaining 2 electrons are shared by 2 hydrogen atoms each.

Hence there are a total of 2 carbon atoms and 4 hydrogen atoms .

STEPS FOR FORMATION OF ETHENE - Teachoo.jpg

General formula for Alkenes

It Is C n H 2n

  • Where n is the number of carbon atoms.

Number of Carbon Atoms (n)

n=2

n=3

n=4

Name of Alkene

Ethene

Propene

Butene

Structure

Structure of Ethene - Teachoo.png
Structure of Propene - Teachoo.png

BUTENE - Teachoo.jpg

Example: Formula for Butene

  • In Propene, there are only 4 carbon atoms.
  • So the formula is,

C n H 2n

  • Putting n=4

            C 4 H 2*4

            C 4 H 8

BUTENE - Teachoo.jpg

Name of Alkene

Formula Derivation C n H 2n

Number of Carbon Atoms (n)

Ethene

C 2 H 4

n=2

Propene

C 3 H 6

n=3

Butene

C 4 H 8

n=4

Pentene

C 5 H 10

n=5

Hexene

C 6 H 12

n=6

Heptene

C 7 H 14

n=7

Octene

C 8 H 16

n=8

Nonene

C 9 H 18

n=9

Decene

C 10 H 20

n=10

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo