1. Lewis Dot Structures-Ions
OH-

2. Resonance Structures When one or more Lewis structure can be drawn
Example
SO3

3. Radicals When there is an odd number of electrons
They are very reactive
Example
NO2

4. Expanded Octet
Elements that can have more than 8 electrons in their outermost shell (examples: sulfur, phosphorous, silicon and chlorine)
Example
PCl5

5. Bonds

6. Bonds
Ionic
Covalent
Polar
Non Polar

7. Bonds Atoms stick together to form molecules
Some atoms want to give electrons, some others want to get electrons. Why? To have 8 electrons in their outermost shell

8. Sometimes… Atoms are transferred (stolen) Atoms are shared evenly
Atoms are shared unevenly

9. Atoms get together to form two types of bonds:
Ionic
Covalent

10. Ionic
metal + nonmetal
Nonmetals are highly electronegative (want an electron) and metals are not very electronegative (want to get rid of an electron)
This bond is not going to be shared. The nonmetal will be “stealing” the metal’s electron

11. Example ionic bond: NaCl

12. Covalent bonds Nonmetal + nonmetal or Nonmetal + metalloid
Because both elements are nonmetals, they tend to have the same electronegativity. So they share electrons

13. Classify the following as ionic or covalent bonds
BrO3 CO
NaCl
Cu2O
Li2O

14. Two types of covalent bonds
Non polar
O-O. Same atom so it has the same electronegativity. They will be sharing electrons evenly
Polar
H-F. Fluorine is more electronegative so electrons will be attracted to it. This bond has an uneven sharing of electrons (H will have a slightly positive charge and F will have a slightly negative charge)

15. Exercises- classify the following as polar covalent or non polar covalent bonds
H-O-H
F-F
NF3
CS2 PC
NPC

16. Another way to determine if a bond is ionic, polar covalent or nonpolar covalent: Look at the electronegative numbers of each element

17. If the difference between the numbers is:
Less than 0.5= non polar covalent bond
Between 0.5 and 1.9= polar covalent bond
Greater than 1.9= ionic bond

18. Summary How do you know whether a bond is ionic or covalent?
1- recognize whether the elements are metals or nonmetals
2- Use the electronegativity chart

19. Come up with five ionic bonds, five polar covalent bonds and five nonpolar covalent bonds