1. Covalent Bonding Lewis Structures

2. Bonding with Nonmetals When no metal is present to donate electrons, nonmetals can share electrons to fill their valence shells.

3. Bonding with Nonmetals Each atom donates an un- paired electron to be shared in the covalent bond. Both atoms have access to this new pair of atoms some of the time.

4. Multiple Covalent Bonds For atoms with more than one unpaired valence electron, multiple covalent bonds between the two atoms can form. Two atoms can form single, double, or triple covalent bonds.

5. Multiple Covalent Bonds Each bond represents a pair of electrons, one from each atom being bonded. More bonds will bring the atoms closer together and the bond will be stronger (more energy required to break it).

6. Lewis Structures Lewis structures show the atom symbols, covalent bonds, and unbonded electrons for covalent molecules.

7. Drawing Lewis Structures 1) Count the total number of valence electrons in all atoms in the molecule. C: 4 O: 6 x 2 = 12 12 + 4 = 16 total val. e -

8. Drawing Lewis Structures 2) The least electronegative, non- hydrogen atom is placed in the center and the other atoms are written surrounding it.

9. Drawing Lewis Structures 3) Draw single covalent bonds connecting the central atom to each outside atom. (subtract used electrons from total) 16 16 - 4 12 12

10. Drawing Lewis Structures 4) Add electrons to fill outside atom valence shells. (substract used electrons from total) 12 12 - 12 0

11. Drawing Lewis Structures 5) Check to make sure the central atom has a full octet. If not, shift pairs from outer electrons into bonds.

12. Lewis Structure Practice 1) Draw a Lewis structure for NH 3.

13. Lewis Structure Practice 2) True or False: The image below is the correct Lewis structure for PF 3.

14. Lewis Structure Practice 3) Draw a Lewis structure for each of the following molecules: a)SiO 2 b)H 2 O c)CH 2 F 2 d)C 2 H 4

15. Naming Molecules Simple covalent molecules are named in the style of ionic compounds (cation then modified anion) based on relative electronegativity values.

16. Naming Molecules NumberPrefixNumberPrefix 1mono6hexa 2di7hepta 3tri8octo 4tetra9nona 5penta10deca

17. Naming Molecules Since multiple possible element ratios exist, we add prefixes to the element names to indicate the subscripts. The prefix “mono” is only used for the more electronegative (second) atom.

18. Naming Practice Name the following covalent molecules: a)SiO 2 b)NO 4 c)N 2 S 3 d)P 3 O 7 e)CO 3