INTRODUCTION

The molecular formula of a molecule can be converted into a model that displays the atoms, bonds, and valence electrons involved in the molecule. These models are known as Lewis Structures, which help us visualize the structure of a molecule on a two-dimensional level. The atoms are represented by the specific elements’ symbol found on the Periodic Table. The bonds, single, double, or triple, are represented by straight lines between atoms. The electrons are represented by dots surrounding the atoms. For example, the molecular formula for water, H2O can be represented by the following 2-D structure:

Depiction of a water molecule where two hydrogen atoms (H) are bonded by a line to an oxygen molecule (O). The oxygen molecule has two lone pairs depicted by two pairs of dots.

Notice how hydrogen and oxygen are represented by their chemical symbols, H and O. There are single bonds shown between the hydrogens and oxygen, and the two sets of lone pairs are represented by two pairs of dots surrounding the atom.

Before we go into the rules for drawing Lewis Structures, be sure you understand the concepts of electron configurations as they are part of the foundation for mastering Lewis Structures.