2. MetalNonmetal Ionic Bond: Metal + Nonmetal Metals: lose valence electrons –form cation –form cation (+ ion) Nonmetals: gain electrons anion –form anion (- ion)

3. IONIC BONDING Involves transfer of electronsInvolves transfer of electrons –electrons go from metal to nonmetal # electrons Lost by Cation (metal)# electrons Lost by Cation (metal) = # electrons Gained by Anion (nonmetal) # electrons Gained by Anion (nonmetal)

4. Metals are losers! Na has configuration 2-8-1 Na loses 1 electron → Na +1 –Na +1 configuration is 2-8 (Ne) takeWhat can take the valence electron from Na??

5. Na metal 

6. Nonmetals are winners! Cl has configuration 2-8-7 Cl gains 1 electron → Cl -1 –Cl -1 configuration 2-8-8 (Ar) donateWhat can donate an electron to Cl ??

7. Cl 2 (g) 

8. Electron is transferred from Na to Cl

9. Structure of Ionic Compounds Ions are attracted to each other by strong electrostatic interactions (between +/- ions) Ions form crystal lattice – regular 3-D pattern or array – Ions are held in fixed positions (solid state)

11. lattice structure  NaCl has its own unique properties

12. The more Na and Cl 2, the larger the resulting NaCl crystal -just keep adding on to it

13. Different representations of a crystal lattice

14. Lewis Diagrams for Ionic Compounds NaCl's Lewis structure: [Na] +1 [ Cl ] -1 Remember: Lewis diagrams show valence electrons!

15. Predicting Ionic Compounds What is ionic compound formed from calcium and iodine?What is ionic compound formed from calcium and iodine? Calcium - metal - 2 valence electrons Calcium - metal - 2 valence electrons - loses both electrons  [Ca] +2 - loses both electrons  [Ca] +2 Iodine - nonmetal - 7 valence electrons Iodine - nonmetal - 7 valence electrons - gains 1 electron  [ ‍ I ] -1 - gains 1 electron  [ ‍ I ] -1 How many iodine ions do you need to make a neutral compound? 2

16. Lewis Diagram of Calcium iodide Ca 2-8-8-2 → Ca +2 2-8-8 I 2-8-18-18-7 → I -1 2-8-18-18-8 [Ca] +2 [:I:] -1 [:I:] -1 or [:I:] -1 [Ca] +2 [:I:] -1 Note: total charge adds up to zero - compounds are neutral - compounds are neutral ···· ·· ·· ······ ··