Introduction: Covalent bonds result from pairs of valence clectrons being shared between atoms, Lewis dot structures use the octet rule to show how the valence clectrons are arranged in molecular compounds. These dot structures show the number of covalent bonds between pairs of atoms in a molecule and the number of electron pairs that exist as lone or nonbonding pairs. There are five basic rules for drawing Lewis dot structures: 1. Calculate the number of valence electrons. Sum the number of valence electrons for all atoms in the formula. For an ion, add one electron for cach negative charge, and subtract one electron for each positive charge. 2. Draw a skeletal siructure. Many chemical formulas show the order in which atoms are connected. Usually, the central atom is surrounded by more electronegative atoms. The exception is that hydrogen will surround a more electroncgative. A skeletal structure will usually be symmetrical. 3. Complete the octets. Place clectrons around the most electroncgative atoms first. Remember that hydrogen only has a single pair of electrons. 4. Place lefiover electrons on the central atom. You should note, that the central atom can have more than an octet. 5. Use multipte bonds to complete the octet of the central atom. Use one or mote of the lone electron pairs on atoms bonded to the eentral atom to form double or triple bonds. Determining Lewis Structures: Draw the Lewis dot structures for the following compotinds. Using the above rales, pat the number of valence electrons in the box below each element. Draw the skeletal and Lewis structures in the indicated boxes. Then determine the number of bonding and nonbonding electron pairs for cach substance