Ch. 14 Periodic Trends

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” Atomic Size Increasing

4. Ionic Size Increase Cations Increase Anions Increase

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

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. (s2 + p6) • - 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 (cont.) Ionization Energy Increase Ionization Energy Increase

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 (cont.) Electronegativity Increase Electronegativity Increase

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