1. Valence Electrons Highest or outermost energy level electrons
Where the chemistry happens! 
Look at principal quantum level n
Sulfur: 1s22s22p63s23p4
Valence electrons are in n = 3 level
Valence electrons = = 6 electrons

2. Atomic Radius (Size) Increases down a group Hydrogen
Francium
Orbitals are getting larger and electrons fill further and further from the nucleus at higher energy levels

3. Atomic Radius (Size)
Decreases across a row (period) – outer electrons in the same energy level
Lithium Fluorine
DECREASES!
More protons in each element as you move across the row. More protons will create a stronger positive force, thus attracting the electrons more strongly, pulling them in and shrinking the size.

4. Clicker #1
Which of the following elements has the largest atomic radius?
A) Ca
B) Al
C) N
D) Sr
E) F

5. General Trend (Atomic Size/Radius)

6. Ionization Energy Decreases down a group Hydrogen
Francium
Orbitals are getting larger and electrons fill further and further from the nucleus at higher energy levels. Electrons are not as tightly bound by the nucleus at higher energy levels so it takes less energy to remove an outer electron.

7. Ionization Energy
Increases across a row (period) – outer electrons in the same energy level
Lithium Fluorine
INCREASES!
More protons in each element as you move across the row. More protons will create a stronger positive force, thus attracting the electrons more strongly and pulling them in closer to the nucleus, requiring MORE energy to remove an outer electron.

8. Clicker #2
Which of the following elements has the largest ionization energy?
A) P
B) Al
C) Cl
D) Ba
E) K

9. General Trend (Ionization Energy)

10. Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure
Molecular Properties

11. Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure
Molecular Properties

12. Bond (Intramolecular)
Force that holds groups of two or more atoms together and makes them function as a unit.
Bond is more stable than the two separated atoms (lower energy state).

13. Ionic Bonding

14. Ionic Bonding

15. Covalent Bonding

16. Electronegativity

17. Covalent Bonding

18. Polar Covalent Bonding

19. Polar Covalent Bonding