Jelena Marinković, Banja Luka
Željko Mikulić, Vukovar
ISOMERISM
MANY THINGS IN NATURE LOOK SIMILAR, BUT THEY ARE COMPLETELY DIFFERENT !
THE IMAGE IS DERIVED FROM CESAR DOGFOOD ADVERTISMENTS
FIND THE DIFFERENCE!
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INTRODUCTION

Isomers are different compounds that have the same molecular
formula. Different compounds means that they have different
physical properties (melting point, boiling point etc.). They may also
have very different chemical properties depending on the type of
isomerism present. Isomers may be divided into

structural isomers, in which the atoms are joined in a different order,
so that they have different structural formulae

stereoisomerism, in which the order in which the atoms are joined is
the same, but the molecules have a different spatial arrangement of
the atoms and hence different three dimensional shapes.
AIM
Students should realize that different structural
formulas can be made from the same
molecular formula.
 The aim is developing the logical way of
thinking, in the propose that the knowledge
could be used in everyday life.
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
We are going to do this topic in different ways,
Željko will do this with second year students
(age 16), during the organic chemistry lessons,
and Jelena will do this with fourth year students
(age 18), during biochemistry lessons.
At the beginning, an open discussion should be
done, about the differences in nature, and how
similar things often are completely deferent.
 During the first class, Željko’ll do the introduction
to alakanes, their structure and properties, and
Jelena will do revision about carbohydrates.
 The aim of the first class is assimilation of basic
knowledge about carbohydrates structure.

During the second class students should make
models of molecules. They have to make
different structure with the same number of
atoms ( making structural isomers based on
the same molecular formula).
 Students should work within the small groups.
 At the and of the hour the have to present they
work.

During the third class, an idea of isomers
should be explained, and how it reacts to
physical and chemical properties.
 Some experiments could be done, depends on
the laboratory equipment.

During the fourth class, the introduction to
alkenes should be done.
 Student should work within groups, making
models of molecules with double bond. They
have to recognize, that rotation around double
bond isn’t possible. They have to make
presentation of their results.
 Based on the results, a definition of the
geometric isomerism should be explained.

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During the fifth class, the knowledge about
structural and geometric isomers should be
applied to the discussion about various
differences in nature.

During the sixth class, students will apply the
gained knowledge about isomers to the new
topic about alkynes.
Jelena will make a different approach.
 First class will start with the revision of the
structural, geometrical and stereo isomers.
 Second class, teacher presents the structure,
properties and appliance of the
monosaccharide.

Students will get cards filled with various
structures of epimers and entiomers of the
monosaccharide.
 They should classify them into groups- L and D
forms and α and β forms.
 They should link the pairs of certain
enatiomers.

Double class is going to be used for a visit to
the Faculty of Chemical Technologies, where
they will define the certain forms of sugars in
the laboratory for the organic chemistry.
 Results will be put down in their note books.

Evaluation class
 The appliance of the gained knowledge in the
further field of biochemistry, e.g. proteins,
nucleid acids etc .
