1. Periodic Trends
You will know what ionization energy is and how it trends on the periodic table
You will know what electron affinity and electronegativity are and how they trend on the periodic table
You will know how cations and anions compare in size to their parent atoms

2. What Are Ions? Na+ Cl- NH4+ SO32-
Ion Definition - An atom or group of bonded
atoms that have a positive or negative charge
Na+
Sodium cation
Cl-
Chloride anion
NH4+
Ammonium cation
SO32-
Sulfite anion
Any process that creates an ion is referred to
as ionization.

3. Ionization Energy A + energy ------> A+ + e-
The energy required to remove one electron
from a neutral atom = ionization energy
A + energy > A+ + e-
For main group elements ….
Ionization energy increases across each period
Ionization energy decreases down each group

5. What determines IE?
The greater the nuclear charge, the greater IE (for periods)
Greater distance from nucleus decreases IE (for groups)

6. Electron Affinity A + e- ------> A- + energy
The energy produced when an electron
is added to neutral atom = electron affinity
A + e > A- + energy

7. Electron Affinity Trend
The energy release when an electron is added to an atom. Most favorable toward NE corner of PT since these atoms have a great affinity for e-.

8. Electronegativity Measure of how much an atom can attract electrons
Higher electronegativity results in higher number
Highest value is Fluorine
Lowest value is Francium
Proposed by Linus Pauling --- Useful in describing
properties of compounds

9. Electronegativity Chart

10. Trends in Ionic Size (page 175-176 book)
Cations are always smaller than the atoms they come from.
Example: Na+ is smaller than Na
Anions are always larger than the atoms they come from.
Example: F- is larger than F

11. Ionic Radii vs Atomic Radii

12. A Closer Look At Ions

13. Putting it all Together

14. Group Properties of Some Main Group Elements
Alkali metals
Alkaline Earth Metals
Halogens
Halogens 2
Noble Gases
Braniac Alkali Metals