Lewis Diagrams

Lewis Dot Diagrams

• Lewis dot diagrams are diagrams in which the valence electrons of an atom are shown as dots distributed around the element’s symbol.

Bonds and Lewis Diagrams

• We can use Lewis diagrams to show the formation of ionic compounds

• We also use Lewis diagrams to show the formation of molecular compounds. A line is used to indicate a shared pair of electrons. These diagrams are also known as Lewis structures or structural formulas

• Molecular compounds can have double (they share two pairs of electrons) and triple bonds (they three pairs of electrons). We show these using double or triple lines

Drawing Lewis Structures

Steps for Drawing Lewis Structures

1. Calculate the total number of valence electrons for the molecule. If drawing the Lewis structure for a ion, subtract one electron per positive charge and add one electron per negative charge

1. Write out all atoms, with the least electronegative atom in the middle

1. Connect surrounding atoms to the central atom with single bonds.

1. Place remaining electrons as lone pairs on surrounding atoms (except hydrogen), completing an octet around each atom

1. Place remaining electrons as lone pairs on the central atom.

1. Shift lone pairs to make double or triple bonds to satisfy the octet rule for all atoms

Example: Lewis Structures

Example: Drawing Lewis Structure with a Double Bond

Example: Drawing Lewis Structures for Ions