1. Periodic Trends

2. WHAT
HOW
WHY
Radius
Electronegativity
Ionization Energy

3. How do we measure atomic radius
Ideally - measure the radius from nucleus to dge of the atoms last filled orbital (valence orbital)
CAN’T!!! --- Because orbitals are just estimations of where electrons might be. The edge is “fuzzy.”
So we measure half the distance between two identical atoms bonded together

4. INCREASES from RIGHT to LEFT, TOP to BOTTOM
Atomic Radius
INCREASES from RIGHT to LEFT, TOP to BOTTOM

5. Why does ATOMIC RADIUS increase the way it does?
DOWN a group – INCREASES Adding more energy levels
ACROSS a period – DECREASES LEFT to RIGHT add more protons, neutrons, and electrons.
SO WHY DOESN’T YOUR RADIUS GET BIGGER????
More protons = the more they can PULL IN e = SMALLER radius
GREATER EFFECTIVE NUCLEAR CHARGE = SMALLER RADIUS

6. Electronegativty
Official Definition of Electronegativity: A measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound What that REALLY means: How strongly it can pull on electrons from another atom

7. INCREASES from LEFT to RIGHT, BOTTOM to TOP
Electronegativity
INCREASES from LEFT to RIGHT, BOTTOM to TOP

8. Why does ELECTRONEGATIVITY increase the way it does?
INCREASES LEFT to RIGHT
Atoms are closer to filling valence shell
DECREASES TOP to BOTTOM Electrons are further from nucleus – not being held onto tightly

9. Ionization Energy
Official Definition of Ionization Energy: The energy required to remove one electron from a neutral atom of an element What that REALLY means: How hard it is to remove an electron from the atom (more energy needed, the harder it is)

10. INCREASES from LEFT to RIGHT, BOTTOM to TOP
Ionization Energy
INCREASES from LEFT to RIGHT, BOTTOM to TOP

11. Why does IONIZATION ENERGY increase the way it does?
Increases left to right because: atoms want to have a full valence shell, so they do not want to give away their electrons
Decreases top to bottom because: electrons are further away from the nucleus so there is not as much attraction. They can be pried loose more easily