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Determination of unshared electron pairs in organic molecule

Determine the number of unshared pairs of electrons on the indicated atoms of the following compounds

a) Oxygen CH3CHO.

b) Oxygen CH3-C=OH+.

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c) Oxygen CH3-C-O .

d) Nitrogen CH3CH2CN.

e) Carbon CH3+

Solution Preview

Only those electrons in an atoms outer most shell are involved in molecular bonds and counted as unshared. Hydrogen has one electron in an 1s orbital.

Carbon has four electrons which are in 4 sp3 orbitals.
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4 H. + .C. gives H-C-H
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H .
In ethylene C has 3 electrons in sp2 orbitals and 1 in a p orbital so 2 H. + 2 .C:

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gives H-C=C-H

In ethyne C has 2 electrons in sp orbitals and 2 in p orbitals giving H-CC-H with a triple bond ...

Solution Summary

This solution provides some background information for determining the number of unshared electron pairs associated with a carbon, oxygen or nitrogen atom in organic molecules. Five examples are presented in a step by step manner.