Chapter 1.3, Problem 5PTS

Interpretation Introduction

Interpretation: The Lewis structures of the small compounds have to be found by using their Lewis dot structures of involving atoms and by following the octet rule.

Concept introduction: The arrangement of atoms that are bonded together determines its constitution and molecular formula of that particular compound.  This concept is referred as structural isomers or in more modern term constitutional isomers.  Each atom has a typical valency or valence which is defined as the ability of an atom to form a chemical bond with other atoms.  For example, carbon has four valence or tetravalent that means carbon has the capacity to form four bonds with other elements or other atoms.  Nitrogen atom is trivalent.  Hydrogen is monovalent in nature.

Lewis dot structures are also called electron dot structures. The diagrams are named after Gilbert N. Lewis, who described them in his 1916 article entitled The Atom and the Molecule.  The number of electrons present in the outermost shell of an atom that participate in forming chemical bonds with other atoms is called valence electrons.  Each group present in the periodic table has specific common valence electrons.  Therefore, the position of the atom in the periodic table should be known for drawing the Lewis dot structures.

The Lewis structure of small compounds can be drawn by combining the Lewis dot structures of the atoms involved in the formation of that compound.  In order to achieve complete noble gas configuration, octet rule is followed to find bonding nature of atoms.  Octet means 8 electrons in their valence shells.  The compounds which obey the octet rule are called stable compounds.

To find: The four constitutional isomers of C₃H₉N, their Lewis structures and the number of lone pair of electrons on the nitrogen atom in each isomer