1. Ch. 14 Periodic Trends Atomic Size – Quantum mechanical model doesn’t sharply define boundary to limit size – Atomic radius: ½ the distance between nuclei of 2 like atoms in a diatomic molecule Atomic radius

2. Atomic size (cont.)

3. Atomic Size (cont.) Atomic Size Increasing “Fatty Francium”

4. Cations Increase Ionic Size Increase Anions Increase

5. Periodic Table of the Elements Atomic Size Ionic Size “Fatty Francium” Fr Trick to Remember

6. Ionization Energy – The energy required to remove an e - from a gaseous atom is called the ionization energy. – As you move from left to right across the periodic table the ionization energy increases b/c of the octet rule

7. Octet Rule: 8 e - in atom’s last energy level. (s 2 + p 6 ) - Noble Gases: highest ionization energies, don’t want to lose e - Li doesn’t take much energy to lose e- F want to gain an e-, therefore takes large amount of energy to pull off an e-

8. Ionization Energy Increase Ionization Energy (cont.)

9. Electronegativity The electronegativity of an element is the tendency for the atoms to attract e- when they are chemically combined with another element Noble Gases have NO electronegativity b/c they don’t gain e - Increase from left to right b/c of octet rule Decrease when move down a group b/c of shielding effect

10. Electronegativity Increase Electronegativity (cont.)

11. Periodic Table of the Elements Atomic Size Increasing Ionic Size Increasing “Fatty Francium” Fr Summary of Trends Ionization Energy Increase Electronegativity Increase F “Friendly Fluorine”