1. Trends in the Periodic Table

2. Periodic Trends
Many trends of elements can be explained by electron configuration and position on the periodic table
What we are going to be looking at:
Atomic Radius
Electronegativity
Ionization Energy

3. Atomic Radius
The distance from the center of the nucleus to the outer most energy shell
Down a Group:
As you go down a group the atomic radius increases

4. Atomic Radius – Across a Period
Have the same number of energy levels but as you go across the number of protons increases pulling in the outer electrons
As you go across the period, the atomic radius becomes smaller

5. Electronegativity
The ability of an atom to steal an electron from another atom.
Electron Thieves

6. Electronegativity – Down a Group
Li has fewer energy levels than sodium making it easier for the protons in the nucleus to grab another atom’s electron
As you move down the electronegativity decreases – its harder to steal electrons

7. Electronegativity – Across a Period
Both have the same number of energy levels, but Be has more protons pulling stronger on another atom’s electrons
As you move across a period, the electronegativity increases – easier to steal electrons

8. Ionization Energy
The ability of an atom to hold onto it’s outer electrons
The bigger the value the harder to lose (the stronger it is holding its electrons)

9. Ionization Energy – Across a Period
Both have the same number of energy levels, but Be has more protons pulling stronger on the outer most electron
As you move across a period, the ionization energy increases (harder to lose outer electrons)

10. Ionization Energy – Down a Group
Na has more energy levels (farther from protons) than Li making it easier to lose the outer electrons
As you move down a group, the ionization energy decreases (easier to lose outer electrons)