A Lewis structure is a diagram representing the covalent bonding of a molecule or ion. It shows how the electrons from one element are bonded to the electrons of the other element via covalent bonds. Covalent bonds are chemical connections or bonds that occur when atoms share electrons. These shared electrons connect the two atoms via a balance of attractive and repulsive forces.
Lewis structures are also referred to as as dot diagrams or electron dot diagrams. These structures were named by Gilbert Newton Lewis when he first published the term in his 1916 paper “The Atom and the Molecule.”
The basic format of a Lewis structure is composed of firstly the chemical symbol of the atom, for example the chemical symbol for Hydrogen is H. Surrounding this symbol, the electrons are drawn as dots. This is the basic form of a Lewis structure, an atomic symbol plus dots showing its electrons. When molecules are drawn, the chemical symbols are arranged such that the electrons which are bonded are drawn side by side. These dots represent the shared electrons forming the covalent bond. A common attribute with electron dot diagrams is that the valence electrons and lone pairs are represented as dots, but also include lines to show the shared pairs in a chemical bond. Single lines for single bonds, two parallel lines for double bonds, and so on.