Lew Dot StructuresA visual representation of covalent compounds

1. Octet Rule◦ Covalent compounds share electrons so that each atom

has an octet of electrons (8) in its highest energy level. Exceptions:

Hydrogen has a full valence shell at 2 electrons Boron has a full valence shell at 6 electrons instead of 8

2. Single Bonds◦ 1 electron pair is shared (a total of 2 electrons)

3. Double Bonds◦ 2 electron pairs are shared (a total of 4 electrons)

4. Triple Bonds◦ 3 electron pairs are shared (a total of 6 electrons)

Before We Begin…..Remember

Electron-dot notation can also be used to represent the structure of molecules, called Lewis Structures.

The pair of dots between the two symbols represents the shared electron pair of the hydrogen-hydrogen covalent bond.

In addition, each fluorine atom is surrounded by three pairs of electrons that are not shared in bonds.

An unshared pair, also called a lone pair, is a pair of electrons that is not involved in bonding and that belongs exclusively to one atom.

What is a Lewis Dot Structure?

Step 1 Get a covalent formula and draw the

electron-dot notation for each atom in the formula.

Step 2 From the electron-dot notation, determine

how many bonds each atom needs to get an octet.

How to Draw a Lewis Dot Structure

Step 3 Determine the central atom (Skip this step if

there are only 2 atoms):◦ Carbon is always the central atom◦ If there is more than 1 carbon they make a chain in the

center. -C-C-C-

◦ Hydrogen & group 17 elements are never in the center.◦ The least electronegative is in the center.

Step 4 Spread the remaining elements around the

central atom & bond each to the center

How to Draw a Lewis Dot Structure